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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.08402">arXiv:2302.08402</a> <span> [<a href="https://arxiv.org/pdf/2302.08402">pdf</a>, <a href="https://arxiv.org/format/2302.08402">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244905">10.1051/0004-6361/202244905 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Continuum reverberation mapping of MCG 08-11-011 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fian%2C+C">C. Fian</a>, <a href="/search/astro-ph?searchtype=author&query=Chelouche%2C+D">D. Chelouche</a>, <a href="/search/astro-ph?searchtype=author&query=Kaspi%2C+S">S. Kaspi</a>, <a href="/search/astro-ph?searchtype=author&query=Figaredo%2C+C+S">C. Sobrino Figaredo</a>, <a href="/search/astro-ph?searchtype=author&query=Lewis%2C+T">T. Lewis</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2302.08402v1-abstract-short" style="display: inline;"> We report the results from a photometric reverberation mapping campaign carried out with the C18 telescope at the Wise Observatory from 2019 to 2020, targeting the active galactic nucleus (AGN) MCG 08-11-011. The monitoring was conducted on a daily basis with specially designed narrow-band filters, spanning from optical to near-infrared wavelengths ($\sim4000$ to $8000$脜) and avoiding prominent br… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.08402v1-abstract-full').style.display = 'inline'; document.getElementById('2302.08402v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.08402v1-abstract-full" style="display: none;"> We report the results from a photometric reverberation mapping campaign carried out with the C18 telescope at the Wise Observatory from 2019 to 2020, targeting the active galactic nucleus (AGN) MCG 08-11-011. The monitoring was conducted on a daily basis with specially designed narrow-band filters, spanning from optical to near-infrared wavelengths ($\sim4000$ to $8000$脜) and avoiding prominent broad emission lines. We aim to measure inter-band continuum time lags, determine the size-wavelength relation, and estimate the host-subtracted AGN luminosity for this system. We used the point-spread function photometry to extract the continuum light curves and measure the inter-band time lags using several methods, including the interpolated cross-correlation function, the z-transformed discrete correlation function, a von Neumann estimator, JAVELIN (in spectroscopic and photometric mode), MICA, and a multivariate correlation function. We find wavelength-dependent lags, $蟿(位)$, up to $\sim$7 days between the multiband light curves of MCG 08-11-011. The observed lags are larger than predictions based on standard thin-disk theory by a factor of $\sim3-7$. We discern a significantly steeper ($蟿\propto 位^{4.74}$) size-wavelength relation than the $蟿\propto 位^{4/3}$ expected for a geometrically thin and optically thick accretion disk, which may result from the contribution of diffuse continuum emission to the flux. These results are similar to those found by previous continuum reverberation mapping campaigns. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.08402v1-abstract-full').style.display = 'none'; document.getElementById('2302.08402v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">arXiv admin note: text overlap with arXiv:2111.07385</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 672, A132 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.07385">arXiv:2111.07385</a> <span> [<a href="https://arxiv.org/pdf/2111.07385">pdf</a>, <a href="https://arxiv.org/format/2111.07385">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202141509">10.1051/0004-6361/202141509 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Continuum reverberation mapping of the quasar PG 2130+099 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fian%2C+C">C. Fian</a>, <a href="/search/astro-ph?searchtype=author&query=Chelouche%2C+D">D. Chelouche</a>, <a href="/search/astro-ph?searchtype=author&query=Kaspi%2C+S">S. Kaspi</a>, <a href="/search/astro-ph?searchtype=author&query=Figaredo%2C+C+S">C. Sobrino Figaredo</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Lewis%2C+T">T. Lewis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2111.07385v1-abstract-short" style="display: inline;"> We present the results of an intensive six-month optical continuum reverberation mapping campaign of the Seyfert 1 galaxy PG 2130+099 at redshift z=0.063. The ground-based photometric monitoring was conducted on a daily basis with the robotic 46cm telescope of the Wise observatory located in Israel. Specially designed narrowband filters were used to observe the central engine of the active galacti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.07385v1-abstract-full').style.display = 'inline'; document.getElementById('2111.07385v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.07385v1-abstract-full" style="display: none;"> We present the results of an intensive six-month optical continuum reverberation mapping campaign of the Seyfert 1 galaxy PG 2130+099 at redshift z=0.063. The ground-based photometric monitoring was conducted on a daily basis with the robotic 46cm telescope of the Wise observatory located in Israel. Specially designed narrowband filters were used to observe the central engine of the active galactic nucleus (AGN), avoiding line contamination from the broad-line region (BLR). We aim to measure inter-band continuum time lags across the optical range and determine the size-wavelength relation for this system. We used two methods, the traditional point-spread function (PSF) photometry and the recently developed proper image subtraction technique, to independently perform the extraction of the continuum light curves. The inter-band time lags are measured with several methods, including the interpolated cross-correlation function, the z-transformed discrete correlation function, a von Neumann estimator, JAVELIN (in spectroscopic mode), and MICA. PG 2130+099 displays correlated variability across the optical range, and we successfully detect significant time lags of up to 3 days between the multiband light curves. Using the flux variation gradient (FVG) method, we determined the AGN's host-galaxy-subtracted rest-frame 5100脜 luminosity at the time of our monitoring campaign with an uncertainty of 18%. While a continuum reprocessing model can fit the data reasonably well, our derived disk sizes are a factor of 2-6 larger than the theoretical disk sizes predicted from the AGN luminosity estimate of PG 2130+099. This result is in agreement with previous studies of AGN/quasars and suggests that the standard Shakura-Sunyaev disk theory has limitations in describing AGN accretion disks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.07385v1-abstract-full').style.display = 'none'; document.getElementById('2111.07385v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 659, A13 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.10977">arXiv:1906.10977</a> <span> [<a href="https://arxiv.org/pdf/1906.10977">pdf</a>, <a href="https://arxiv.org/ps/1906.10977">ps</a>, <a href="https://arxiv.org/format/1906.10977">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201629648">10.1051/0004-6361/201629648 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The ESO supernovae type Ia progenitor survey (SPY) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Napiwotzki%2C+R">R. Napiwotzki</a>, <a href="/search/astro-ph?searchtype=author&query=Karl%2C+C+A">C. A. Karl</a>, <a href="/search/astro-ph?searchtype=author&query=Lisker%2C+T">T. Lisker</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Drechsel%2C+H">H. Drechsel</a>, <a href="/search/astro-ph?searchtype=author&query=Heber%2C+U">U. Heber</a>, <a href="/search/astro-ph?searchtype=author&query=Homeier%2C+D">D. Homeier</a>, <a href="/search/astro-ph?searchtype=author&query=Koester%2C+D">D. Koester</a>, <a href="/search/astro-ph?searchtype=author&query=Leibundgut%2C+B">B. Leibundgut</a>, <a href="/search/astro-ph?searchtype=author&query=Marsh%2C+T+R">T. R. Marsh</a>, <a href="/search/astro-ph?searchtype=author&query=Moehler%2C+S">S. Moehler</a>, <a href="/search/astro-ph?searchtype=author&query=Nelemans%2C+G">G. Nelemans</a>, <a href="/search/astro-ph?searchtype=author&query=Reimers%2C+D">D. Reimers</a>, <a href="/search/astro-ph?searchtype=author&query=Renzini%2C+A">A. Renzini</a>, <a href="/search/astro-ph?searchtype=author&query=Stroer%2C+A">A. Stroer</a>, <a href="/search/astro-ph?searchtype=author&query=Yungelson%2C+L">L. Yungelson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.10977v2-abstract-short" style="display: inline;"> Close double degenerate binaries are one of the favoured progenitor channels for type Ia supernovae, but it is unclear how many suitable systems there are in the Galaxy. We report results of a large radial velocity survey for double degenerate (DD) binaries using the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY). Exposures taken at different epochs are checked for radial vel… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.10977v2-abstract-full').style.display = 'inline'; document.getElementById('1906.10977v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.10977v2-abstract-full" style="display: none;"> Close double degenerate binaries are one of the favoured progenitor channels for type Ia supernovae, but it is unclear how many suitable systems there are in the Galaxy. We report results of a large radial velocity survey for double degenerate (DD) binaries using the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY). Exposures taken at different epochs are checked for radial velocity shifts indicating close binary systems. We observed 689 targets classified as DA (displaying hydrogen-rich atmospheres), of which 46 turned out to possess a cool companion. We measured radial velocities (RV) of the remaining 643 DA white dwarfs. We managed to secure observations at two or more epochs for 625 targets, supplemented by eleven objects meeting our selection criteria from literature. The data reduction and analysis methods applied to the survey data are described in detail. The sample contains 39 double degenerate binaries, only four of which were previously known. 20 are double-lined systems, in which features from both components are visible, the other 19 are single-lined binaries. We provide absolute RVs transformed to the heliocentric system suitable for kinematic studies. Our sample is large enough to sub-divide by mass: 16 out of 44 low mass targets (<= 0.45 Msun) are detected as DDs, while just 23 of the remaining 567 with multiple spectra and mass >0.45 Msun are double. Although the detected fraction amongst the low mass objects (36.4 +/- 7.3%) is significantly higher than for the higher-mass, carbon/oxygen-core dominated part of the sample (3.9 +/- 0.8%), it is lower than the detection efficiency based upon companion star masses >= 0.05 Msun. This suggests either companion stars of mass < 0.05 Msun, or that some of the low mass white dwarfs are single. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.10977v2-abstract-full').style.display = 'none'; document.getElementById('1906.10977v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in A&A. 59 pages. Think before you print: large tables in the appendix</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 638, A131 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.00135">arXiv:1805.00135</a> <span> [<a href="https://arxiv.org/pdf/1805.00135">pdf</a>, <a href="https://arxiv.org/ps/1805.00135">ps</a>, <a href="https://arxiv.org/format/1805.00135">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/sty1162">10.1093/mnras/sty1162 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Axions and the luminosity function of white dwarfs. The thin and thick disks, and the halo </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">Jordi Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">Enrique Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Torres%2C+S">Santiago Torres</a>, <a href="/search/astro-ph?searchtype=author&query=Cojocaru%2C+R">Roxana Cojocaru</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">Silvia Catalan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1805.00135v1-abstract-short" style="display: inline;"> The evolution of white dwarfs is a simple gravothermal process of cooling. Since the shape of their luminosity function is sensitive to the characteristic cooling time, it is possible to use its slope to test the existence of additional sources or sinks of energy, such as those predicted by alternative physical theories. The aim of this paper is to study if the changes in the slope of the white dw… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.00135v1-abstract-full').style.display = 'inline'; document.getElementById('1805.00135v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.00135v1-abstract-full" style="display: none;"> The evolution of white dwarfs is a simple gravothermal process of cooling. Since the shape of their luminosity function is sensitive to the characteristic cooling time, it is possible to use its slope to test the existence of additional sources or sinks of energy, such as those predicted by alternative physical theories. The aim of this paper is to study if the changes in the slope of the white dwarf luminosity function around bolometric magnitudes ranging from 8 to 10 and previously attributed to axion emission are, effectively, a consequence of the existence of axions and not an artifact introduced by the star formatio rate. We compute theoretical luminosity functions of the thin and thick disk, and of the stellar halo including axion emission and we compare them with the existing observed luminosity functions. Since these stellar populations have different star formation histories, the slope change should be present in all of them at the same place if it is due to axions or any other intrinsic cooling mechanism. The signature of an unexpected cooling seems to be present in the luminosity functions of the thin and thick disks, as well as in the halo luminosity function. This additional cooling is compatible with axion emission, thus supporting the idea that DFSZ axions, with a mass in the range of 4 to 10 meV, could exist. If this were the case, these axions could be detected by the future solar axioscope IAXO. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.00135v1-abstract-full').style.display = 'none'; document.getElementById('1805.00135v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 April, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures, accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1708.09394">arXiv:1708.09394</a> <span> [<a href="https://arxiv.org/pdf/1708.09394">pdf</a>, <a href="https://arxiv.org/ps/1708.09394">ps</a>, <a href="https://arxiv.org/format/1708.09394">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx2243">10.1093/mnras/stx2243 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-band photometry and spectroscopy of an all-sky sample of bright white dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Raddi%2C+R">R. Raddi</a>, <a href="/search/astro-ph?searchtype=author&query=Fusillo%2C+N+P+G">N. P. Gentile Fusillo</a>, <a href="/search/astro-ph?searchtype=author&query=Pala%2C+A+F">A. F. Pala</a>, <a href="/search/astro-ph?searchtype=author&query=Hermes%2C+J+J">J. J. Hermes</a>, <a href="/search/astro-ph?searchtype=author&query=Gaensicke%2C+B+T">B. T. Gaensicke</a>, <a href="/search/astro-ph?searchtype=author&query=Chote%2C+P">P. Chote</a>, <a href="/search/astro-ph?searchtype=author&query=Hollands%2C+M+A">M. A. Hollands</a>, <a href="/search/astro-ph?searchtype=author&query=Henden%2C+A">A. Henden</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Geier%2C+S">S. Geier</a>, <a href="/search/astro-ph?searchtype=author&query=Koester%2C+D">D. Koester</a>, <a href="/search/astro-ph?searchtype=author&query=Munari%2C+U">U. Munari</a>, <a href="/search/astro-ph?searchtype=author&query=Napiwotzki%2C+R">R. Napiwotzki</a>, <a href="/search/astro-ph?searchtype=author&query=Tremblay%2C+P+-">P. -E. Tremblay</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1708.09394v1-abstract-short" style="display: inline;"> The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will obtain space-based uninterrupted light curves for a large sample of bright white dwarfs distributed across the entire sky, providing a very rich resource for asteroseismological studies and the search for transits from planetary debris. We have compiled an all-sky catalogue of ultraviolet, optical, and infrared photometry as well… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.09394v1-abstract-full').style.display = 'inline'; document.getElementById('1708.09394v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1708.09394v1-abstract-full" style="display: none;"> The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will obtain space-based uninterrupted light curves for a large sample of bright white dwarfs distributed across the entire sky, providing a very rich resource for asteroseismological studies and the search for transits from planetary debris. We have compiled an all-sky catalogue of ultraviolet, optical, and infrared photometry as well as proper motions, which we propose as an essential tool for the preliminary identification and characterisation of potential targets. We present data for 1864 known white dwarfs and 305 high-probability white dwarf candidates brighter than 17 mag. We describe the spectroscopic follow-up of 135 stars, of which 82 are white dwarfs and 25 are hot subdwarfs. The new confirmed stars include six pulsating white dwarf candidates (ZZ Cetis), and nine white dwarf binaries with a cool main-sequence companion. We identify one star with a spectroscopic distance of only 25 pc from the Sun. Around the time TESS is launched, we foresee that all white dwarfs in this sample will have trigonometric parallaxes measured by the ESA Gaia mission next year. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.09394v1-abstract-full').style.display = 'none'; document.getElementById('1708.09394v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication on MNRAS. 21 pages, 8 tables. Machine readable tables, which will be made also available through VizieR, are also included</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1601.02019">arXiv:1601.02019</a> <span> [<a href="https://arxiv.org/pdf/1601.02019">pdf</a>, <a href="https://arxiv.org/ps/1601.02019">ps</a>, <a href="https://arxiv.org/format/1601.02019">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw042">10.1093/mnras/stw042 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A search for white dwarfs in the Galactic plane: the field and the open cluster population </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Raddi%2C+R">R. Raddi</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Gaensicke%2C+B+T">B. T. Gaensicke</a>, <a href="/search/astro-ph?searchtype=author&query=Hermes%2C+J+J">J. J. Hermes</a>, <a href="/search/astro-ph?searchtype=author&query=Napiwotzki%2C+R">R. Napiwotzki</a>, <a href="/search/astro-ph?searchtype=author&query=Koester%2C+D">D. Koester</a>, <a href="/search/astro-ph?searchtype=author&query=Tremblay%2C+P+-">P. -E. Tremblay</a>, <a href="/search/astro-ph?searchtype=author&query=Barentsen%2C+G">G. Barentsen</a>, <a href="/search/astro-ph?searchtype=author&query=Farnhill%2C+H+J">H. J. Farnhill</a>, <a href="/search/astro-ph?searchtype=author&query=Mohr-Smith%2C+M">M. Mohr-Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Drew%2C+J+E">J. E. Drew</a>, <a href="/search/astro-ph?searchtype=author&query=Groot%2C+P+J">P. J. Groot</a>, <a href="/search/astro-ph?searchtype=author&query=Guzman-Ramirez%2C+L">L. Guzman-Ramirez</a>, <a href="/search/astro-ph?searchtype=author&query=Parker%2C+Q+A">Q. A. Parker</a>, <a href="/search/astro-ph?searchtype=author&query=Steeghs%2C+D">D. Steeghs</a>, <a href="/search/astro-ph?searchtype=author&query=Zijlstra%2C+A">A. Zijlstra</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1601.02019v2-abstract-short" style="display: inline;"> We investigated the prospects for systematic searches of white dwarfs at low Galactic latitudes, using the VLT Survey Telescope (VST) H$伪$ Photometric Survey of the Galactic plane and Bulge (VPHAS+). We targeted 17 white dwarf candidates along sightlines of known open clusters, aiming to identify potential cluster members. We confirmed all the 17 white dwarf candidates from blue/optical spectrosco… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.02019v2-abstract-full').style.display = 'inline'; document.getElementById('1601.02019v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1601.02019v2-abstract-full" style="display: none;"> We investigated the prospects for systematic searches of white dwarfs at low Galactic latitudes, using the VLT Survey Telescope (VST) H$伪$ Photometric Survey of the Galactic plane and Bulge (VPHAS+). We targeted 17 white dwarf candidates along sightlines of known open clusters, aiming to identify potential cluster members. We confirmed all the 17 white dwarf candidates from blue/optical spectroscopy, and we suggest five of them to be likely cluster members. We estimated progenitor ages and masses for the candidate cluster members, and compared our findings to those for other cluster white dwarfs. A white dwarf in NGC 3532 is the most massive known cluster member (1.13 M$_{\odot}$), likely with an oxygen-neon core, for which we estimate an $8.8_{-4.3}^{+1.2}$ M$_{\odot}$ progenitor, close to the mass-divide between white dwarf and neutron star progenitors. A cluster member in Ruprecht 131 is a magnetic white dwarf, whose progenitor mass exceeded 2-3 M$_{\odot}$. We stress that wider searches, and improved cluster distances and ages derived from data of the ESA Gaia mission, will advance the understanding of the mass-loss processes for low- to intermediate-mass stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.02019v2-abstract-full').style.display = 'none'; document.getElementById('1601.02019v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 January, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 January, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 11 figures, 5 tables. Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1512.02608">arXiv:1512.02608</a> <span> [<a href="https://arxiv.org/pdf/1512.02608">pdf</a>, <a href="https://arxiv.org/format/1512.02608">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Supernova 2014J at M82: II. Direct Analysis of Spectra Obtained with Isaac Newton and William Herschel Telescopes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Vallely%2C+P">Patrick Vallely</a>, <a href="/search/astro-ph?searchtype=author&query=Moreno-Raya%2C+M+E">M. E. Moreno-Raya</a>, <a href="/search/astro-ph?searchtype=author&query=Baron%2C+E">E. Baron</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiz-Lapuente%2C+P">Pilar Ruiz-Lapuente</a>, <a href="/search/astro-ph?searchtype=author&query=Dominguez%2C+I">I. Dominguez</a>, <a href="/search/astro-ph?searchtype=author&query=Galbany%2C+L">Lluis Galbany</a>, <a href="/search/astro-ph?searchtype=author&query=Hernandez%2C+J+I+G">J. I. Gonzalez Hernandez</a>, <a href="/search/astro-ph?searchtype=author&query=Mendez%2C+J">J. Mendez</a>, <a href="/search/astro-ph?searchtype=author&query=Hamuy%2C+M">M. Hamuy</a>, <a href="/search/astro-ph?searchtype=author&query=Lopez-Sanchez%2C+A+R">A. R. Lopez-Sanchez</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Cooke%2C+E">E. Cooke</a>, <a href="/search/astro-ph?searchtype=author&query=Farina%2C+C">C. Farina</a>, <a href="/search/astro-ph?searchtype=author&query=Genova-Santos%2C+R">R. Genova-Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Karjalainen%2C+R">R. Karjalainen</a>, <a href="/search/astro-ph?searchtype=author&query=Lietzen%2C+H">H. Lietzen</a>, <a href="/search/astro-ph?searchtype=author&query=McCormac%2C+J">J. McCormac</a>, <a href="/search/astro-ph?searchtype=author&query=Riddick%2C+F">F. Riddick</a>, <a href="/search/astro-ph?searchtype=author&query=Rubino-Martin%2C+J+A">J. A. Rubino-Martin</a>, <a href="/search/astro-ph?searchtype=author&query=Skillen%2C+I">I. Skillen</a>, <a href="/search/astro-ph?searchtype=author&query=Tudor%2C+V">V. Tudor</a>, <a href="/search/astro-ph?searchtype=author&query=Vaduvescu%2C+O">O. Vaduvescu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1512.02608v2-abstract-short" style="display: inline;"> We analyze a time series of optical spectra of SN~2014J from almost two weeks prior to maximum to nearly four months after maximum. We perform our analysis using the SYNOW code, which is well suited to track the distribution of the ions with velocity in the ejecta. We show that almost all of the spectral features during the entire epoch can be identified with permitted transitions of the common io… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.02608v2-abstract-full').style.display = 'inline'; document.getElementById('1512.02608v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1512.02608v2-abstract-full" style="display: none;"> We analyze a time series of optical spectra of SN~2014J from almost two weeks prior to maximum to nearly four months after maximum. We perform our analysis using the SYNOW code, which is well suited to track the distribution of the ions with velocity in the ejecta. We show that almost all of the spectral features during the entire epoch can be identified with permitted transitions of the common ions found in normal SNe Ia in agreement with previous studies. We show that 2014J is a relatively normal SN Ia. At early times the spectral features are dominated by Si II, S II, Mg II, and Ca II. These ions persist to maximum light with the appearance of Na I and Mg I. At later times iron-group elements also appear, as expected in the stratified abundance model of the formation of normal type Ia SNe. We do not find significant spectroscopic evidence for oxygen, until 100 days after maximum light. The +100 day identification of oxygen is tentative, and would imply significant mixing of unburned or only slight processed elements down to a velocity of 6,000 km/s. Our results are in relatively good agreement with other analyses in the IR. We briefly compare SN 2011fe to SN 2014J and conclude that the differences could be due to different central densities at ignition or differences in the C/O ratio of the progenitors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.02608v2-abstract-full').style.display = 'none'; document.getElementById('1512.02608v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 May, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 December, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 6 figures, 4 tables, MNRAS, in press</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1510.06596">arXiv:1510.06596</a> <span> [<a href="https://arxiv.org/pdf/1510.06596">pdf</a>, <a href="https://arxiv.org/format/1510.06596">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw026">10.1093/mnras/stw026 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> SN 2014J at M82: I. A middle-class type Ia supernova by all spectroscopic metrics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Galbany%2C+L">L. Galbany</a>, <a href="/search/astro-ph?searchtype=author&query=Moreno-Raya%2C+M+E">M. E. Moreno-Raya</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiz-Lapuente%2C+P">P. Ruiz-Lapuente</a>, <a href="/search/astro-ph?searchtype=author&query=Hern%C3%A1ndez%2C+J+I+G">J. I. Gonz谩lez Hern谩ndez</a>, <a href="/search/astro-ph?searchtype=author&query=M%C3%A9ndez%2C+J">J. M茅ndez</a>, <a href="/search/astro-ph?searchtype=author&query=Vallely%2C+P">P. Vallely</a>, <a href="/search/astro-ph?searchtype=author&query=Baron%2C+E">E. Baron</a>, <a href="/search/astro-ph?searchtype=author&query=Dom%C3%ADnguez%2C+I">I. Dom铆nguez</a>, <a href="/search/astro-ph?searchtype=author&query=Hamuy%2C+M">M. Hamuy</a>, <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez-S%C3%A1nchez%2C+A+R">A. R. L贸pez-S谩nchez</a>, <a href="/search/astro-ph?searchtype=author&query=Moll%C3%A1%2C+M">M. Moll谩</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Cooke%2C+E+A">E. A. Cooke</a>, <a href="/search/astro-ph?searchtype=author&query=Fari%C3%B1a%2C+C">C. Fari帽a</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%A9nova-Santos%2C+R">R. G茅nova-Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Karjalainen%2C+R">R. Karjalainen</a>, <a href="/search/astro-ph?searchtype=author&query=Lietzen%2C+H">H. Lietzen</a>, <a href="/search/astro-ph?searchtype=author&query=McCormac%2C+J">J. McCormac</a>, <a href="/search/astro-ph?searchtype=author&query=Riddick%2C+F+C">F. C. Riddick</a>, <a href="/search/astro-ph?searchtype=author&query=Rubi%C3%B1o-Mart%C3%ADn%2C+J+A">J. A. Rubi帽o-Mart铆n</a>, <a href="/search/astro-ph?searchtype=author&query=Skillen%2C+I">I. Skillen</a>, <a href="/search/astro-ph?searchtype=author&query=Tudor%2C+V">V. Tudor</a>, <a href="/search/astro-ph?searchtype=author&query=Vaduvescu%2C+O">O. Vaduvescu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1510.06596v2-abstract-short" style="display: inline;"> We present the intensive spectroscopic follow up of the type Ia supernova (SN Ia) 2014J in the starburst galaxy M82. Twenty-seven optical spectra have been acquired from January 22nd to September 1st 2014 with the Isaac Newton (INT) and William Herschel (WHT) Telescopes. After correcting the observations for the recession velocity of M82 and for Milky Way and host galaxy extinction, we measured ex… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.06596v2-abstract-full').style.display = 'inline'; document.getElementById('1510.06596v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.06596v2-abstract-full" style="display: none;"> We present the intensive spectroscopic follow up of the type Ia supernova (SN Ia) 2014J in the starburst galaxy M82. Twenty-seven optical spectra have been acquired from January 22nd to September 1st 2014 with the Isaac Newton (INT) and William Herschel (WHT) Telescopes. After correcting the observations for the recession velocity of M82 and for Milky Way and host galaxy extinction, we measured expansion velocities from spectral line blueshifts and pseudo-equivalent width of the strongest features in the spectra, which gives an idea on how elements are distributed within the ejecta. We position SN 2014J in the Benetti (2005), Branch et al. (2006) and Wang et al. (2009) diagrams. These diagrams are based on properties of the Si II features and provide dynamical and chemical information about the SN ejecta. The nearby SN 2011fe, which showed little evidence for reddening in its host galaxy, is shown as a reference for comparisons. SN 2014J is a border-line object between the Core-normal (CN) and Broad-line (BL) groups, which corresponds to an intermediate position between Low Velocity Gradient (LVG) and High Velocity Gradient (HVG) objects. SN 2014J follows the R(Si II)-螖m15 correlation, which confirms its classification as a relatively normal SN Ia. Our description of the SN Ia in terms of the evolution of the pseudo-equivalent width of various ions as well as the position in the various diagrams put this specific SN Ia into the overall sample of SN Ia. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.06596v2-abstract-full').style.display = 'none'; document.getElementById('1510.06596v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 January, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 10 Figures, 4 Tables. Accepted in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1502.05223">arXiv:1502.05223</a> <span> [<a href="https://arxiv.org/pdf/1502.05223">pdf</a>, <a href="https://arxiv.org/ps/1502.05223">ps</a>, <a href="https://arxiv.org/format/1502.05223">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201219095">10.1051/0004-6361/201219095 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Analysis of combined radial velocities and activity of BD+20 1790: evidence supporting the existence of a planetary companion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hern%C3%A1n-Obispo%2C+M">M. Hern谩n-Obispo</a>, <a href="/search/astro-ph?searchtype=author&query=Tuomi%2C+M">M. Tuomi</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%A1lvez-Ortiz%2C+M+C">M. C. G谩lvez-Ortiz</a>, <a href="/search/astro-ph?searchtype=author&query=Golovin%2C+A">A. Golovin</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+J+R">J. R. Barnes</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H+R+A">H. R. A. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Kane%2C+S+R">S. R. Kane</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D">D. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Jenkins%2C+J+S">J. S. Jenkins</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+P">P. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Anglada-Escud%C3%A9%2C+G">G. Anglada-Escud茅</a>, <a href="/search/astro-ph?searchtype=author&query=Marsden%2C+S+C">S. C. Marsden</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Jeffers%2C+S+V">S. V. Jeffers</a>, <a href="/search/astro-ph?searchtype=author&query=de+Castro%2C+E">E. de Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Cornide%2C+M">M. Cornide</a>, <a href="/search/astro-ph?searchtype=author&query=Garc%C3%A9s%2C+A">A. Garc茅s</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+M+I">M. I. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Gorlova%2C+N">N. Gorlova</a>, <a href="/search/astro-ph?searchtype=author&query=Andreev%2C+M">M. Andreev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1502.05223v1-abstract-short" style="display: inline;"> This paper presents the simultaneous Bayesian analysis of the radial velocity and activity indices for the K5Ve active star BD+20 1790, that was proposed to host a close-in massive planet by Hern谩n-Obispo et al. (2010). The Bayesian analysis supports the hypothesis of a planetary companion. We present a new orbital solution after removing the two main contributions to the stellar jitter, one that… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.05223v1-abstract-full').style.display = 'inline'; document.getElementById('1502.05223v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1502.05223v1-abstract-full" style="display: none;"> This paper presents the simultaneous Bayesian analysis of the radial velocity and activity indices for the K5Ve active star BD+20 1790, that was proposed to host a close-in massive planet by Hern谩n-Obispo et al. (2010). The Bayesian analysis supports the hypothesis of a planetary companion. We present a new orbital solution after removing the two main contributions to the stellar jitter, one that varies with the photometric period and another that varies with the synodic period of the star+planet system. We use a new method to determine these jitter components, considering them as a second and third signals in the system. A discussion on possible magnetic star-planet-interaction is included, based on the Bayesian analysis of the activity indices. We propose two possible sources for flare events of this star: one related to the geometry of the system and the relative movement of the star+planet, and a second one purely stochastic source that is related to the evolution of stellar active regions. Also, we observe for the first time the magnetic field of the star, from spectropolarimetric data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.05223v1-abstract-full').style.display = 'none'; document.getElementById('1502.05223v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 February, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 18 figures, accepted for publication at A\&A (!2 January 2015)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.3235">arXiv:1410.3235</a> <span> [<a href="https://arxiv.org/pdf/1410.3235">pdf</a>, <a href="https://arxiv.org/ps/1410.3235">ps</a>, <a href="https://arxiv.org/format/1410.3235">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stu1662">10.1093/mnras/stu1662 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The first planet detected in the WTS: an inflated hot-Jupiter in a 3.35 day orbit around a late F-star [ERRATUM] </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cappetta%2C+M">M. Cappetta</a>, <a href="/search/astro-ph?searchtype=author&query=Saglia%2C+R+P">R. P. Saglia</a>, <a href="/search/astro-ph?searchtype=author&query=Birkby%2C+J+L">J. L. Birkby</a>, <a href="/search/astro-ph?searchtype=author&query=Koppenhoefer%2C+J">J. Koppenhoefer</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Hodgkin%2C+S+T">S. T. Hodgkin</a>, <a href="/search/astro-ph?searchtype=author&query=Cruz%2C+P">P. Cruz</a>, <a href="/search/astro-ph?searchtype=author&query=Kovacs%2C+G">G. Kovacs</a>, <a href="/search/astro-ph?searchtype=author&query=Sipocz%2C+B">B. Sipocz</a>, <a href="/search/astro-ph?searchtype=author&query=Barrado%2C+D">D. Barrado</a>, <a href="/search/astro-ph?searchtype=author&query=Nefs%2C+B">B. Nefs</a>, <a href="/search/astro-ph?searchtype=author&query=Pavlenko%2C+Y+V">Y. V. Pavlenko</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=del+Burgo%2C+C">C. del Burgo</a>, <a href="/search/astro-ph?searchtype=author&query=Martin%2C+E+L">E. L. Martin</a>, <a href="/search/astro-ph?searchtype=author&query=Snellen%2C+I">I. Snellen</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+J">J. Barnes</a>, <a href="/search/astro-ph?searchtype=author&query=Campbell%2C+D+A">D. A. Campbell</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Galvez-Ortiz%2C+M+C">M. C. Galvez-Ortiz</a>, <a href="/search/astro-ph?searchtype=author&query=Goulding%2C+N">N. Goulding</a>, <a href="/search/astro-ph?searchtype=author&query=Haswell%2C+C">C. Haswell</a>, <a href="/search/astro-ph?searchtype=author&query=Ivanyuk%2C+O">O. Ivanyuk</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H">H. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Kuznetsov%2C+M">M. Kuznetsov</a> , et al. (13 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1410.3235v1-abstract-short" style="display: inline;"> We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope (UKIRT) in August 2007. Light curves comprising almost 1200 epochs with a photometric precision of better than 1 per cent to J ~ 16 were constructed for ~60000 stars and searched for periodic transit signals. For one of the most p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.3235v1-abstract-full').style.display = 'inline'; document.getElementById('1410.3235v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.3235v1-abstract-full" style="display: none;"> We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope (UKIRT) in August 2007. Light curves comprising almost 1200 epochs with a photometric precision of better than 1 per cent to J ~ 16 were constructed for ~60000 stars and searched for periodic transit signals. For one of the most promising transiting candidates, high-resolution spectra taken at the Hobby-Eberly Telescope (HET) allowed us to estimate the spectroscopic parameters of the host star, a late-F main sequence dwarf (V=16.13) with possibly slightly subsolar metallicity, and to measure its radial velocity variations. The combined analysis of the light curves and spectroscopic data resulted in an orbital period of the substellar companion of 3.35 days, a planetary mass of 4.01 +- 0.35 Mj and a planetary radius of 1.49+0.16-0.18 Rj. WTS-1b has one of the largest radius anomalies among the known hot Jupiters in the mass range 3-5 Mj. The high irradiation from the host star ranks the planet in the pM class. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.3235v1-abstract-full').style.display = 'none'; document.getElementById('1410.3235v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 October, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 10 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1409.3125">arXiv:1409.3125</a> <span> [<a href="https://arxiv.org/pdf/1409.3125">pdf</a>, <a href="https://arxiv.org/format/1409.3125">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stu1895">10.1093/mnras/stu1895 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The substellar companion in the eclipsing white dwarf binary SDSS J141126.20+200911.1 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Littlefair%2C+S+P">S. P. Littlefair</a>, <a href="/search/astro-ph?searchtype=author&query=Casewell%2C+S+L">S. L. Casewell</a>, <a href="/search/astro-ph?searchtype=author&query=Parsons%2C+S+G">S. G. Parsons</a>, <a href="/search/astro-ph?searchtype=author&query=Dhillon%2C+V+S">V. S. Dhillon</a>, <a href="/search/astro-ph?searchtype=author&query=Marsh%2C+T+R">T. R. Marsh</a>, <a href="/search/astro-ph?searchtype=author&query=Gaensicke%2C+B+T+G">B. T. G. Gaensicke</a>, <a href="/search/astro-ph?searchtype=author&query=Bloemen%2C+S">S. Bloemen</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Irawati%2C+P">P. Irawati</a>, <a href="/search/astro-ph?searchtype=author&query=Hardy%2C+L+K">L. K. Hardy</a>, <a href="/search/astro-ph?searchtype=author&query=Mcallister%2C+M">M. Mcallister</a>, <a href="/search/astro-ph?searchtype=author&query=Bours%2C+M+C+P">M. C. P. Bours</a>, <a href="/search/astro-ph?searchtype=author&query=Richichi%2C+A">Andrea Richichi</a>, <a href="/search/astro-ph?searchtype=author&query=Burleigh%2C+M+R">M. R. Burleigh</a>, <a href="/search/astro-ph?searchtype=author&query=Burningham%2C+B">B. Burningham</a>, <a href="/search/astro-ph?searchtype=author&query=Breedt%2C+E">E. Breedt</a>, <a href="/search/astro-ph?searchtype=author&query=Kerry%2C+P">P. Kerry</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1409.3125v1-abstract-short" style="display: inline;"> We present high time resolution SDSS-$g'$ and SDSS-$z'$ light curves of the primary eclipse in SDSS J141126.20+200911.1, together with time-resolved X-Shooter spectroscopy and near-infrared $JHK_{s}$ photometry. Our observations confirm the substellar nature of the companion, making SDSS J141126.20+200911.1 the first eclipsing white dwarf/brown dwarf binary known. We measure a (white dwarf model d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.3125v1-abstract-full').style.display = 'inline'; document.getElementById('1409.3125v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1409.3125v1-abstract-full" style="display: none;"> We present high time resolution SDSS-$g'$ and SDSS-$z'$ light curves of the primary eclipse in SDSS J141126.20+200911.1, together with time-resolved X-Shooter spectroscopy and near-infrared $JHK_{s}$ photometry. Our observations confirm the substellar nature of the companion, making SDSS J141126.20+200911.1 the first eclipsing white dwarf/brown dwarf binary known. We measure a (white dwarf model dependent) mass and radius for the brown dwarf companion of $M_{2} = 0.050 \pm 0.002$ $M_{\odot}$ and $R_{2} = 0.072 \pm 0.004$ $M_{\odot}$, respectively. The lack of a robust detection of the companion light in the $z'$-band eclipse constrains the spectral type of the companion to be later than L5. Comparing the NIR photometry to the expected white dwarf flux reveals a clear $K_s$-band excess, suggesting a spectral type in the range L7-T1. The radius measurement is consistent with the predictions of evolutionary models, and suggests a system age in excess of three Gyr. The low companion mass is inconsistent with the inferred spectral type of L7-T1, instead predicting a spectral type nearer T5. This indicates that irradiation of the companion in SDSS J1411 could be causing a significant temperature increase, at least on one hemisphere. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.3125v1-abstract-full').style.display = 'none'; document.getElementById('1409.3125v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 10 figures, accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1407.6163">arXiv:1407.6163</a> <span> [<a href="https://arxiv.org/pdf/1407.6163">pdf</a>, <a href="https://arxiv.org/ps/1407.6163">ps</a>, <a href="https://arxiv.org/format/1407.6163">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> White paper: Gaia and the end states of stellar evolution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Barstow%2C+M+A">M. A Barstow</a>, <a href="/search/astro-ph?searchtype=author&query=Casewell%2C+S+L">S. L. Casewell</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Copperwheat%2C+C">C. Copperwheat</a>, <a href="/search/astro-ph?searchtype=author&query=Gaensicke%2C+B">B. Gaensicke</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Hambly%2C+N">N. Hambly</a>, <a href="/search/astro-ph?searchtype=author&query=Heber%2C+U">U. Heber</a>, <a href="/search/astro-ph?searchtype=author&query=Holberg%2C+J">J. Holberg</a>, <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Jeffery%2C+S">S. Jeffery</a>, <a href="/search/astro-ph?searchtype=author&query=Jordan%2C+S">S. Jordan</a>, <a href="/search/astro-ph?searchtype=author&query=Lawrie%2C+K+A">K. A. Lawrie</a>, <a href="/search/astro-ph?searchtype=author&query=Lynas-Gray%2C+A+E">A. E. Lynas-Gray</a>, <a href="/search/astro-ph?searchtype=author&query=Maccarone%2C+T">T. Maccarone</a>, <a href="/search/astro-ph?searchtype=author&query=Marsh%2C+T">T. Marsh</a>, <a href="/search/astro-ph?searchtype=author&query=Parsons%2C+S">S. Parsons</a>, <a href="/search/astro-ph?searchtype=author&query=Silvotti%2C+R">R. Silvotti</a>, <a href="/search/astro-ph?searchtype=author&query=Subasavage%2C+J">J. Subasavage</a>, <a href="/search/astro-ph?searchtype=author&query=Torres%2C+S">S. Torres</a>, <a href="/search/astro-ph?searchtype=author&query=Wheatley%2C+P">P. Wheatley</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1407.6163v4-abstract-short" style="display: inline;"> This is the product of a Gaia GREAT workshop on "Gaia and the end states of stellar evolution" held at the University of Leicester in April 2011. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1407.6163v4-abstract-full" style="display: none;"> This is the product of a Gaia GREAT workshop on "Gaia and the end states of stellar evolution" held at the University of Leicester in April 2011. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.6163v4-abstract-full').style.display = 'none'; document.getElementById('1407.6163v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 August, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 July, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2014. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1407.5415">arXiv:1407.5415</a> <span> [<a href="https://arxiv.org/pdf/1407.5415">pdf</a>, <a href="https://arxiv.org/ps/1407.5415">ps</a>, <a href="https://arxiv.org/format/1407.5415">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stu1465">10.1093/mnras/stu1465 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> WASP 1628+10 - an EL CVn-type binary with a very-low-mass stripped-red-giant star and multi-periodic pulsations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Maxted%2C+P+F+L">P. F. L. Maxted</a>, <a href="/search/astro-ph?searchtype=author&query=Serenelli%2C+A+M">A. M. Serenelli</a>, <a href="/search/astro-ph?searchtype=author&query=Marsh%2C+T+R">T. R. Marsh</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Mahtani%2C+D+P">D. P. Mahtani</a>, <a href="/search/astro-ph?searchtype=author&query=Dhillon%2C+V+S">V. S. Dhillon</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1407.5415v2-abstract-short" style="display: inline;"> The star 1SWASP J162842.31+101416.7 (WASP 1628+10) is one of several EL CVn-type stars recently identified using the WASP database, i.e., an eclipsing binary star in which an A-type dwarf star (WASP 1628+10A) eclipses the remnant of a disrupted red giant star (WASP1628+10B). We have measured the masses, radii and luminosities of the stars in WASP 1628+10 using photometry obtained in three bands (u… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.5415v2-abstract-full').style.display = 'inline'; document.getElementById('1407.5415v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1407.5415v2-abstract-full" style="display: none;"> The star 1SWASP J162842.31+101416.7 (WASP 1628+10) is one of several EL CVn-type stars recently identified using the WASP database, i.e., an eclipsing binary star in which an A-type dwarf star (WASP 1628+10A) eclipses the remnant of a disrupted red giant star (WASP1628+10B). We have measured the masses, radii and luminosities of the stars in WASP 1628+10 using photometry obtained in three bands (u', g', r') with the Ultracam instrument and medium-resolution spectroscopy. The properties of the remnant are well-matched by models for stars in a rarely-observed state evolving to higher effective temperatures at nearly constant luminosity prior to becoming a very low-mass white dwarf composed almost entirely of helium, i.e., we confirm that WASP 1628+10B is a pre-He-WD. WASP 1628+10A appears to be a normal A2V star with a mass of $1.36 \pm 0.05 M_{\odot}$. By fitting models to the spectrum of this star around the H$纬$ line we find that it has an effective temperature T$_{\rm eff,A} = 7500 \pm 200$K and a metallicity [Fe/H]$ = -0.3 \pm 0.3$. The mass of WASP 1628+10B is only $0.135 \pm 0.02M_{\odot}$. The effective temperature of this pre-He-WD is approximately 9200K. The Ultracam photometry of WASP 1628+10 shows variability at several frequencies around 40 cycles per day, which is typical for $未$ Sct-type pulsations often observed in early A-type stars like WASP 1628+10A. We also observe frequencies near 114 cycles/day and 129 cycles/day, much higher than the frequencies normally seen in $未$ Sct stars. Additional photometry through the primary eclipse will be required to confirm that these higher frequencies are due to pulsations in WASP 1628+10B. If confirmed, this would be only the second known example of a pre-He-WD showing high-frequency pulsations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.5415v2-abstract-full').style.display = 'none'; document.getElementById('1407.5415v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 July, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 July, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 7 figures. Accepted for publication in MNRAS. Added missing bibliography</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1406.6698">arXiv:1406.6698</a> <span> [<a href="https://arxiv.org/pdf/1406.6698">pdf</a>, <a href="https://arxiv.org/ps/1406.6698">ps</a>, <a href="https://arxiv.org/format/1406.6698">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stu1295">10.1093/mnras/stu1295 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High Proper Motion Objects from the UKIDSS Galactic Plane Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smith%2C+L">L. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Lucas%2C+P+W">P. W. Lucas</a>, <a href="/search/astro-ph?searchtype=author&query=Bunce%2C+R">R. Bunce</a>, <a href="/search/astro-ph?searchtype=author&query=Burningham%2C+B">B. Burningham</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H+R+A">H. R. A. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Smart%2C+R+L">R. L. Smart</a>, <a href="/search/astro-ph?searchtype=author&query=Skrzypek%2C+N">N. Skrzypek</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+D+R">D. R. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Faherty%2C+J">J. Faherty</a>, <a href="/search/astro-ph?searchtype=author&query=Barentsen%2C+G">G. Barentsen</a>, <a href="/search/astro-ph?searchtype=author&query=Drew%2C+J+E">J. E. Drew</a>, <a href="/search/astro-ph?searchtype=author&query=Andrei%2C+A+H">A. H. Andrei</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Redburn%2C+D">D. Redburn</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1406.6698v1-abstract-short" style="display: inline;"> The UKIDSS Galactic Plane Survey (GPS) began in 2005 as a 7 year effort to survey ~1800 square degrees of the northern Galactic plane in the J, H, and K passbands. The survey included a second epoch of K band data, with a baseline of 2 to 8 years, for the purpose of investigating variability and measuring proper motions. We have calculated proper motions for 167 Million sources in a 900 square deg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.6698v1-abstract-full').style.display = 'inline'; document.getElementById('1406.6698v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1406.6698v1-abstract-full" style="display: none;"> The UKIDSS Galactic Plane Survey (GPS) began in 2005 as a 7 year effort to survey ~1800 square degrees of the northern Galactic plane in the J, H, and K passbands. The survey included a second epoch of K band data, with a baseline of 2 to 8 years, for the purpose of investigating variability and measuring proper motions. We have calculated proper motions for 167 Million sources in a 900 square degree area located at l > 60 degrees in order to search for new high proper motion objects. Visual inspection has verified 617 high proper motion sources (> 200 mas/yr) down to K=17, of which 153 are new discoveries. Among these we have a new spectroscopically confirmed T5 dwarf, an additional T dwarf with estimated type T6, 13 new L dwarf candidates, and two new common proper motion systems containing ultracool dwarf candidates. We provide improved proper motions for an additional 12 high proper motion stars that were independently discovered in the WISE dataset during the course of this investigation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.6698v1-abstract-full').style.display = 'none'; document.getElementById('1406.6698v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 June, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in the MNRAS main journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1403.6045">arXiv:1403.6045</a> <span> [<a href="https://arxiv.org/pdf/1403.6045">pdf</a>, <a href="https://arxiv.org/format/1403.6045">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201220596">10.1051/0004-6361/201220596 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gaia photometry for white dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Carrasco%2C+J+M">J. M. Carrasco</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Jordi%2C+C">C. Jordi</a>, <a href="/search/astro-ph?searchtype=author&query=Tremblay%2C+P+E">P. E. Tremblay</a>, <a href="/search/astro-ph?searchtype=author&query=Napiwotzki%2C+R">R. Napiwotzki</a>, <a href="/search/astro-ph?searchtype=author&query=Luri%2C+X">X. Luri</a>, <a href="/search/astro-ph?searchtype=author&query=Robin%2C+A+C">A. C. Robin</a>, <a href="/search/astro-ph?searchtype=author&query=Kowalski%2C+P+M">P. M Kowalski</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1403.6045v1-abstract-short" style="display: inline;"> Context. White dwarfs can be used to study the structure and evolution of the Galaxy by analysing their luminosity function and initial mass function. Among them, the very cool white dwarfs provide the information for the early ages of each population. Because white dwarfs are intrinsically faint only the nearby (about 20 pc) sample is reasonably complete. The Gaia space mission will drastically i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.6045v1-abstract-full').style.display = 'inline'; document.getElementById('1403.6045v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1403.6045v1-abstract-full" style="display: none;"> Context. White dwarfs can be used to study the structure and evolution of the Galaxy by analysing their luminosity function and initial mass function. Among them, the very cool white dwarfs provide the information for the early ages of each population. Because white dwarfs are intrinsically faint only the nearby (about 20 pc) sample is reasonably complete. The Gaia space mission will drastically increase the sample of known white dwarfs through its 5-6 years survey of the whole sky up to magnitude V = 20-25. Aims. We provide a characterisation of Gaia photometry for white dwarfs to better prepare for the analysis of the scientific output of the mission. Transformations between some of the most common photometric systems and Gaia passbands are derived. We also give estimates of the number of white dwarfs of the different galactic populations that will be observed. Methods. Using synthetic spectral energy distributions and the most recent Gaia transmission curves, we computed colours of three different types of white dwarfs (pure hydrogen, pure helium, and mixed composition with H/He= 0.1). With these colours we derived transformations to other common photometric systems (Johnson-Cousins, Sloan Digital Sky Survey, and 2MASS). We also present numbers of white dwarfs predicted to be observed by Gaia. Results. We provide relationships and colour-colour diagrams among different photometric systems to allow the prediction and/or study of the Gaia white dwarf colours. We also include estimates of the number of sources expected in every galactic population and with a maximum parallax error. Gaia will increase the sample of known white dwarfs tenfold to about 200 000. Gaia will be able to observe thousands of very cool white dwarfs for the first time, which will greatly improve our understanding of these stars and early phases of star formation in our Galaxy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.6045v1-abstract-full').style.display = 'none'; document.getElementById('1403.6045v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 March, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 39 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1402.5416">arXiv:1402.5416</a> <span> [<a href="https://arxiv.org/pdf/1402.5416">pdf</a>, <a href="https://arxiv.org/ps/1402.5416">ps</a>, <a href="https://arxiv.org/format/1402.5416">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stu343">10.1093/mnras/stu343 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> WTS-2 b: a hot Jupiter orbiting near its tidal destruction radius around a K-dwarf </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Birkby%2C+J+L">J. L. Birkby</a>, <a href="/search/astro-ph?searchtype=author&query=Cappetta%2C+M">M. Cappetta</a>, <a href="/search/astro-ph?searchtype=author&query=Cruz%2C+P">P. Cruz</a>, <a href="/search/astro-ph?searchtype=author&query=Koppenhoefer%2C+J">J. Koppenhoefer</a>, <a href="/search/astro-ph?searchtype=author&query=Ivanyuk%2C+O">O. Ivanyuk</a>, <a href="/search/astro-ph?searchtype=author&query=Mustill%2C+A+J">A. J. Mustill</a>, <a href="/search/astro-ph?searchtype=author&query=Hodgkin%2C+S+T">S. T. Hodgkin</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Sip%C5%91cz%2C+B">B. Sip艖cz</a>, <a href="/search/astro-ph?searchtype=author&query=Kov%C3%A1cs%2C+G">G. Kov谩cs</a>, <a href="/search/astro-ph?searchtype=author&query=Saglia%2C+R">R. Saglia</a>, <a href="/search/astro-ph?searchtype=author&query=Pavlenko%2C+Y">Y. Pavlenko</a>, <a href="/search/astro-ph?searchtype=author&query=Barrado%2C+D">D. Barrado</a>, <a href="/search/astro-ph?searchtype=author&query=Bayo%2C+A">A. Bayo</a>, <a href="/search/astro-ph?searchtype=author&query=Campbell%2C+D">D. Campbell</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%A1lvez-Ortiz%2C+M+-">M. -C. G谩lvez-Ortiz</a>, <a href="/search/astro-ph?searchtype=author&query=Kenworthy%2C+M">M. Kenworthy</a>, <a href="/search/astro-ph?searchtype=author&query=Mart%C3%ADn%2C+J+L+E+L">J. Lillo-Box E. L. Mart铆n</a>, <a href="/search/astro-ph?searchtype=author&query=Mislis%2C+D">D. Mislis</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mooij%2C+E+J+W">E. J. W. de Mooij</a>, <a href="/search/astro-ph?searchtype=author&query=Nefs%2C+S+V">S. V. Nefs</a>, <a href="/search/astro-ph?searchtype=author&query=Snellen%2C+I+A+G">I. A. G. Snellen</a>, <a href="/search/astro-ph?searchtype=author&query=Stoev%2C+H">H. Stoev</a> , et al. (12 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1402.5416v1-abstract-short" style="display: inline;"> We report the discovery of WTS-2 b, an unusually close-in 1.02-day hot Jupiter (Mp=1.12MJ, Rp=1.363RJ) orbiting a K2V star, which has a possible gravitationally-bound M-dwarf companion at 0.6 arcsec separation contributing ~20 percent of the total flux in the observed J-band light curve. The planet is only 1.5 times the separation from its host star at which it would be destroyed by Roche lobe ove… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.5416v1-abstract-full').style.display = 'inline'; document.getElementById('1402.5416v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1402.5416v1-abstract-full" style="display: none;"> We report the discovery of WTS-2 b, an unusually close-in 1.02-day hot Jupiter (Mp=1.12MJ, Rp=1.363RJ) orbiting a K2V star, which has a possible gravitationally-bound M-dwarf companion at 0.6 arcsec separation contributing ~20 percent of the total flux in the observed J-band light curve. The planet is only 1.5 times the separation from its host star at which it would be destroyed by Roche lobe overflow, and has a predicted remaining lifetime of just ~40 Myr, assuming a tidal dissipation quality factor of Q'*=10^6. Q'* is a key factor in determining how frictional processes within a host star affect the orbital evolution of its companion giant planets, but it is currently poorly constrained by observations. We calculate that the orbital decay of WTS-2 b would correspond to a shift in its transit arrival time of T_shift~17 seconds after 15 years assuming Q'*=10^6. A shift less than this would place a direct observational constraint on the lower limit of Q'* in this system. We also report a correction to the previously published expected T_shift for WASP-18 b, finding that T_shift=356 seconds after 10 years for Q'*=10^6, which is much larger than the estimated 28 seconds quoted in WASP-18 b discovery paper. We attempted to constrain Q'* via a study of the entire population of known transiting hot Jupiters, but our results were inconclusive, requiring a more detailed treatment of transit survey sensitivities at long periods. We conclude that the most informative and straight-forward constraints on Q'* will be obtained by direct observational measurements of the shift in transit arrival times in individual hot Jupiter systems. We show that this is achievable across the mass spectrum of exoplanet host stars within a decade, and will directly probe the effects of stellar interior structure on tidal dissipation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.5416v1-abstract-full').style.display = 'none'; document.getElementById('1402.5416v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 February, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 16 figures, 6 tables, accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1311.1227">arXiv:1311.1227</a> <span> [<a href="https://arxiv.org/pdf/1311.1227">pdf</a>, <a href="https://arxiv.org/ps/1311.1227">ps</a>, <a href="https://arxiv.org/format/1311.1227">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stt2156">10.1093/mnras/stt2156 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A 1500 deg$^2$ Near Infrared Proper Motion Catalogue from the UKIDSS Large Area Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smith%2C+L">L. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Lucas%2C+P+W">P. W. Lucas</a>, <a href="/search/astro-ph?searchtype=author&query=Burningham%2C+B">B. Burningham</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H+R+A">H. R. A. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Smart%2C+R+L">R. L. Smart</a>, <a href="/search/astro-ph?searchtype=author&query=Andrei%2C+A+H">A. H. Andrei</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D">D. Pinfield</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1311.1227v1-abstract-short" style="display: inline;"> The UKIDSS Large Area Survey (LAS) began in 2005, with the start of the UKIDSS program as a 7 year effort to survey roughly 4000 deg$^2$ at high galactic latitudes in Y, J, H and K bands. The survey also included a significant quantity of 2-epoch J band observations, with an epoch baseline greater than 2 years to calculate proper motions. We present a near infrared proper motion catalogue for the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.1227v1-abstract-full').style.display = 'inline'; document.getElementById('1311.1227v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1311.1227v1-abstract-full" style="display: none;"> The UKIDSS Large Area Survey (LAS) began in 2005, with the start of the UKIDSS program as a 7 year effort to survey roughly 4000 deg$^2$ at high galactic latitudes in Y, J, H and K bands. The survey also included a significant quantity of 2-epoch J band observations, with an epoch baseline greater than 2 years to calculate proper motions. We present a near infrared proper motion catalogue for the 1500 deg$^2$ of the 2 epoch LAS data, which includes 135,625 stellar sources and a further 88,324 with ambiguous morphological classifications, all with motions detected above the 5$蟽$ level. We developed a custom proper motion pipeline which we describe here. Our catalogue agrees well with the proper motion data supplied for a 300 deg$^2$ subset in the current WFCAM Science Archive (WSA) tenth data release (DR10) catalogue, and in various optical catalogues, but it benefits from a larger matching radius and hence a larger upper proper motion detection limit. We provide absolute proper motions, using LAS galaxies for the relative to absolute correction. By using local 2nd order polynomial transformations, as opposed to linear transformations in the WSA, we correct better for any local distortions in the focal plane, not including the radial distortion that is removed by the UKIDSS pipeline. We present the results of proper motion searches for new brown dwarfs and white dwarfs. We discuss 41 sources in the WSA DR10 overlap with our catalogue with proper motions $>$300 $mas yr^{-1}$, several of which are new detections. We present 15 new candidate ultra-cool dwarf binary systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.1227v1-abstract-full').style.display = 'none'; document.getElementById('1311.1227v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 November, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">27 pages, 15 figures, and 8 tables. Public catalogue available at http://star.herts.ac.uk/~lsmith/</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1306.3060">arXiv:1306.3060</a> <span> [<a href="https://arxiv.org/pdf/1306.3060">pdf</a>, <a href="https://arxiv.org/ps/1306.3060">ps</a>, <a href="https://arxiv.org/format/1306.3060">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stt1030">10.1093/mnras/stt1030 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A spectroscopic and proper motion search of Sloan digital Sky Survey: red subdwarfs in binary systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+Z+H">Z. H. Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Burningham%2C+B">B. Burningham</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H+R+A">H. R. A. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Galvez-Ortiz%2C+M+C">M. C. Galvez-Ortiz</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Smart%2C+R+L">R. L. Smart</a>, <a href="/search/astro-ph?searchtype=author&query=Lepine%2C+S">S. Lepine</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+J+R+A">J. R. A. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Pavlenko%2C+Y+V">Ya. V. Pavlenko</a>, <a href="/search/astro-ph?searchtype=author&query=Murray%2C+D+N">D. N. Murray</a>, <a href="/search/astro-ph?searchtype=author&query=Kuznetsov%2C+M+K">M. K. Kuznetsov</a>, <a href="/search/astro-ph?searchtype=author&query=Day-Jones%2C+A+C">A. C. Day-Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Gomes%2C+J">J. Gomes</a>, <a href="/search/astro-ph?searchtype=author&query=Marocco%2C+F">F. Marocco</a>, <a href="/search/astro-ph?searchtype=author&query=Sipocz%2C+B">B. Sipocz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1306.3060v2-abstract-short" style="display: inline;"> Red subdwarfs in binary systems are crucial for both model calibration and spectral classification. We search for red subdwarfs in binary systems from a sample of high proper motion objects with Sloan digital Sky Survey spectroscopy. We present here discoveries from this search, as well as highlight several additional objects of interest. We find 30 red subdwarfs in wide binary systems including:… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.3060v2-abstract-full').style.display = 'inline'; document.getElementById('1306.3060v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1306.3060v2-abstract-full" style="display: none;"> Red subdwarfs in binary systems are crucial for both model calibration and spectral classification. We search for red subdwarfs in binary systems from a sample of high proper motion objects with Sloan digital Sky Survey spectroscopy. We present here discoveries from this search, as well as highlight several additional objects of interest. We find 30 red subdwarfs in wide binary systems including: two with spectral type of esdM5.5, 6 companions to white dwarfs and 3 carbon enhanced red subdwarfs with normal red subdwarf companions. 15 red subdwarfs in our sample are partially resolved close binary systems. With this binary sample, we estimate the low limit of the red subdwarf binary fraction of ~ 10%. We find that the binary fraction goes down with decreasing masses and metallicities of red subdwarfs. A spectroscopic esdK7 subdwarf + white dwarf binary candidate is also reported. 30 new M subdwarfs have spectral type of >= M6 in our sample. We also derive relationships between spectral types and absolute magnitudes in the optical and near-infrared for M and L subdwarfs, and we present an M subdwarf sample with measured U, V, W space velocities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.3060v2-abstract-full').style.display = 'none'; document.getElementById('1306.3060v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 July, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 June, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 19 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1304.7652">arXiv:1304.7652</a> <span> [<a href="https://arxiv.org/pdf/1304.7652">pdf</a>, <a href="https://arxiv.org/ps/1304.7652">ps</a>, <a href="https://arxiv.org/format/1304.7652">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Axion cooling of white dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia--Berro%2C+E">E. Garcia--Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Salaris%2C+M">M. Salaris</a>, <a href="/search/astro-ph?searchtype=author&query=Torres%2C+S">S. Torres</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1304.7652v1-abstract-short" style="display: inline;"> The evolution of white dwarfs is a simple gravothermal process. This process can be tested in two ways, through the luminosity function of these stars and through the secular variation of the period of pulsation of those stars that are variable. Here we show how the mass of the axion can be constrained using the white dwarf luminosity function. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1304.7652v1-abstract-full" style="display: none;"> The evolution of white dwarfs is a simple gravothermal process. This process can be tested in two ways, through the luminosity function of these stars and through the secular variation of the period of pulsation of those stars that are variable. Here we show how the mass of the axion can be constrained using the white dwarf luminosity function. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1304.7652v1-abstract-full').style.display = 'none'; document.getElementById('1304.7652v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 April, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Proceedings of the 8th Patras Workshop on Axions, WIMPs and WISPs</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1211.5288">arXiv:1211.5288</a> <span> [<a href="https://arxiv.org/pdf/1211.5288">pdf</a>, <a href="https://arxiv.org/format/1211.5288">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2012.21932.x">10.1111/j.1365-2966.2012.21932.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> J band Variability of M Dwarfs in the WFCAM Transit Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Goulding%2C+N+T">N. T. Goulding</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+J+R">J. R. Barnes</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Kov%C3%A1cs%2C+G">G. Kov谩cs</a>, <a href="/search/astro-ph?searchtype=author&query=Birkby%2C+J">J. Birkby</a>, <a href="/search/astro-ph?searchtype=author&query=Hodgkin%2C+S">S. Hodgkin</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Sip%C5%91cz%2C+B">B. Sip艖cz</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H+R+A">H. R. A. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=del+Burgo%2C+C">C. del Burgo</a>, <a href="/search/astro-ph?searchtype=author&query=Jeffers%2C+S+V">S. V. Jeffers</a>, <a href="/search/astro-ph?searchtype=author&query=Nefs%2C+S">S. Nefs</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%A1lvez-Ortiz%2C+M+-">M. -C. G谩lvez-Ortiz</a>, <a href="/search/astro-ph?searchtype=author&query=Martin%2C+E+L">E. L. Martin</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1211.5288v2-abstract-short" style="display: inline;"> We present an analysis of the photometric variability of M dwarfs in the WFCAM Transit Survey. Although periodic lightcurve variability in low mass stars is generally dominated by photospheric star spot activity, M dwarf variability in the J band has not been as thoroughly investigated as at visible wavelengths. Spectral type estimates for a sample of over 200,000 objects are made using spectral t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1211.5288v2-abstract-full').style.display = 'inline'; document.getElementById('1211.5288v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1211.5288v2-abstract-full" style="display: none;"> We present an analysis of the photometric variability of M dwarfs in the WFCAM Transit Survey. Although periodic lightcurve variability in low mass stars is generally dominated by photospheric star spot activity, M dwarf variability in the J band has not been as thoroughly investigated as at visible wavelengths. Spectral type estimates for a sample of over 200,000 objects are made using spectral type-colour relations, and over 9600 dwarfs (J<17) with spectral types later than K7 were found. The light curves of the late-type sample are searched for periodicity using a Lomb-Scargle periodogram analysis. A total of 68 periodic variable M dwarfs are found in the sample with periods ranging from 0.16 days to 90.33 days, with amplitudes in the range of ~0.009 to ~0.115 in the J band. We simulate active M dwarfs with a range of latitude-independent spot coverages and estimate a periodically variable fractions of 1-3 per cent for stars where spots cover more than 10 per cent of the star's surface. Our simulated spot distributions indicate that operating in the J band, where spot contrast ratios are minimised, enables variability in only the most active of stars to be detected. These findings affirm the benefits of using the $J$ band for planetary transit searches compared to visible bands. We also serendipitously find a 螖J>0.2 mag flaring event from an M4V star in our sample. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1211.5288v2-abstract-full').style.display = 'none'; document.getElementById('1211.5288v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 December, 2012; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 November, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 18 figures, 2 tables, accepted in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1211.2161">arXiv:1211.2161</a> <span> [<a href="https://arxiv.org/pdf/1211.2161">pdf</a>, <a href="https://arxiv.org/ps/1211.2161">ps</a>, <a href="https://arxiv.org/format/1211.2161">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> The impact of mergers in the mass distribution of white dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Hernanz%2C+M">M. Hernanz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1211.2161v1-abstract-short" style="display: inline;"> Recent surveys have allowed to derive the white dwarf mass distribution with reasonable accuracy. This distribution shows a noticeable degree of structure that it is often attributed to the evolution of close binaries in general, and to mergers in particular. To analyze if the origin of this structure can be attributed to the merger of double white dwarfs, we have used a simplified population synt… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1211.2161v1-abstract-full').style.display = 'inline'; document.getElementById('1211.2161v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1211.2161v1-abstract-full" style="display: none;"> Recent surveys have allowed to derive the white dwarf mass distribution with reasonable accuracy. This distribution shows a noticeable degree of structure that it is often attributed to the evolution of close binaries in general, and to mergers in particular. To analyze if the origin of this structure can be attributed to the merger of double white dwarfs, we have used a simplified population synthesis model that retains the essential processes of formation of double degenerate binaries. Special care has been taken to avoid artifacts introduced by discontinuities in the distribution functions. Our result is that these structures are not probably due to mergers, but they can provide a deep insight on the evolution of close binary systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1211.2161v1-abstract-full').style.display = 'none'; document.getElementById('1211.2161v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 November, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Proceedings of the 18th European White Dwarf Workshop</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1210.1217">arXiv:1210.1217</a> <span> [<a href="https://arxiv.org/pdf/1210.1217">pdf</a>, <a href="https://arxiv.org/ps/1210.1217">ps</a>, <a href="https://arxiv.org/format/1210.1217">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2012.21937.x">10.1111/j.1365-2966.2012.21937.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The first planet detected in the WTS: an inflated hot-Jupiter in a 3.35 day orbit around a late F-star </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cappetta%2C+M">M. Cappetta</a>, <a href="/search/astro-ph?searchtype=author&query=Saglia%2C+R+P">R. P. Saglia</a>, <a href="/search/astro-ph?searchtype=author&query=Birkby%2C+J+L">J. L. Birkby</a>, <a href="/search/astro-ph?searchtype=author&query=Koppenhoefer%2C+J">J. Koppenhoefer</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Hodgkin%2C+S+T">S. T. Hodgkin</a>, <a href="/search/astro-ph?searchtype=author&query=Cruz%2C+P">P. Cruz</a>, <a href="/search/astro-ph?searchtype=author&query=Kov%C3%A1cs%2C+G">G. Kov谩cs</a>, <a href="/search/astro-ph?searchtype=author&query=Sip%C3%B6cz%2C+B">B. Sip枚cz</a>, <a href="/search/astro-ph?searchtype=author&query=Barrado%2C+D">D. Barrado</a>, <a href="/search/astro-ph?searchtype=author&query=Nefs%2C+B">B. Nefs</a>, <a href="/search/astro-ph?searchtype=author&query=Pavlenko%2C+Y+V">Y. V. Pavlenko</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=del+Burgo%2C+C">C. del Burgo</a>, <a href="/search/astro-ph?searchtype=author&query=Mart%C3%ADn%2C+E+L">E. L. Mart铆n</a>, <a href="/search/astro-ph?searchtype=author&query=Snellen%2C+I">I. Snellen</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+J">J. Barnes</a>, <a href="/search/astro-ph?searchtype=author&query=Bayo%2C+A+M">A. M. Bayo</a>, <a href="/search/astro-ph?searchtype=author&query=Campbell%2C+D+A">D. A. Campbell</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%A1lvez-Ortiz%2C+M+C">M. C. G谩lvez-Ortiz</a>, <a href="/search/astro-ph?searchtype=author&query=Goulding%2C+N">N. Goulding</a>, <a href="/search/astro-ph?searchtype=author&query=Haswell%2C+C">C. Haswell</a>, <a href="/search/astro-ph?searchtype=author&query=Ivanyuk%2C+O">O. Ivanyuk</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H">H. Jones</a> , et al. (14 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1210.1217v1-abstract-short" style="display: inline;"> We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope. Light curves comprising almost 1200 epochs with a photometric precision of better than 1 per cent to J=16 were constructed for 60000 stars and searched for periodic transit signals. For one of the most promising transiting candid… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1210.1217v1-abstract-full').style.display = 'inline'; document.getElementById('1210.1217v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1210.1217v1-abstract-full" style="display: none;"> We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope. Light curves comprising almost 1200 epochs with a photometric precision of better than 1 per cent to J=16 were constructed for 60000 stars and searched for periodic transit signals. For one of the most promising transiting candidates, high-resolution spectra taken at the Hobby-Eberly Telescope allowed us to estimate the spectroscopic parameters of the host star, a late-F main sequence dwarf (V=16.13) with possibly slightly subsolar metallicity, and to measure its radial velocity variations. The combined analysis of the light curves and spectroscopic data resulted in an orbital period of the substellar companion of 3.35 days, a planetary mass of 4.01+-0.35 Mj and a planetary radius of 1.49+-0.17 Rj. WTS-1b has one of the largest radius anomalies among the known hot Jupiters in the mass range 3-5 Mj. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1210.1217v1-abstract-full').style.display = 'none'; document.getElementById('1210.1217v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 October, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 10 figures, 9 tables, accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1209.1403">arXiv:1209.1403</a> <span> [<a href="https://arxiv.org/pdf/1209.1403">pdf</a>, <a href="https://arxiv.org/format/1209.1403">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201220191">10.1051/0004-6361/201220191 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The brightest pure-H ultracool white dwarf </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Tremblay%2C+P+-">P. -E. Tremblay</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+L+C">L. C. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+Z+H">Z. H. Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Napiwotzki%2C+R">R. Napiwotzki</a>, <a href="/search/astro-ph?searchtype=author&query=Marocco%2C+F">F. Marocco</a>, <a href="/search/astro-ph?searchtype=author&query=Day-Jones%2C+A+C">A. C. Day-Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Gomes%2C+J">J. Gomes</a>, <a href="/search/astro-ph?searchtype=author&query=Forde%2C+K+P">K. P. Forde</a>, <a href="/search/astro-ph?searchtype=author&query=Lucas%2C+P+W">P. W. Lucas</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H+R+A">H. R. A. Jones</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1209.1403v1-abstract-short" style="display: inline;"> We report the identification of LSR J0745+2627 in the United Kingdom InfraRed Telescope Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) as a cool white dwarf with kinematics and age compatible with the thick-disk/halo population. LSR J0745+2627 has a high proper motion (890 mas/yr) and a high reduced proper motion value in the J band (H_J=21.87). We show how the infrared-reduced proper m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1209.1403v1-abstract-full').style.display = 'inline'; document.getElementById('1209.1403v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1209.1403v1-abstract-full" style="display: none;"> We report the identification of LSR J0745+2627 in the United Kingdom InfraRed Telescope Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) as a cool white dwarf with kinematics and age compatible with the thick-disk/halo population. LSR J0745+2627 has a high proper motion (890 mas/yr) and a high reduced proper motion value in the J band (H_J=21.87). We show how the infrared-reduced proper motion diagram is useful for selecting a sample of cool white dwarfs with low contamination. LSR J0745+2627 is also detected in the Sloan Digital Sky Survey (SDSS) and the Wide-field Infrared Survey Explorer (WISE). We have spectroscopically confirmed this object as a cool white dwarf using X-Shooter on the Very Large Telescope. A detailed analysis of its spectral energy distribution reveals that its atmosphere is compatible with a pure-H composition model with an effective temperature of 3880+-90 K. This object is the brightest pure-H ultracool white dwarf (Teff<4000 K) ever identified. We have constrained the distance (24-45 pc), space velocities and age considering different surface gravities. The results obtained suggest that LSR J0745+2627 belongs to the thick-disk/halo population and is also one of the closest ultracool white dwarfs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1209.1403v1-abstract-full').style.display = 'none'; document.getElementById('1209.1403v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 September, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 7 figures, accepted for publication in A&A Letters</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1205.6806">arXiv:1205.6806</a> <span> [<a href="https://arxiv.org/pdf/1205.6806">pdf</a>, <a href="https://arxiv.org/ps/1205.6806">ps</a>, <a href="https://arxiv.org/format/1205.6806">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-6256/144/4/93">10.1088/0004-6256/144/4/93 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Effects of Close Companions (and Rotation) on the Magnetic Activity of M Dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Morgan%2C+D+P">Dylan P. Morgan</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Garc%C3%A9s%2C+A">Ane Garc茅s</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">Silvia Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Dhital%2C+S">Saurav Dhital</a>, <a href="/search/astro-ph?searchtype=author&query=Fuchs%2C+M">Miriam Fuchs</a>, <a href="/search/astro-ph?searchtype=author&query=Silvestri%2C+N+M">Nicole M. Silvestri</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1205.6806v2-abstract-short" style="display: inline;"> We present a study of close white dwarf and M dwarf (WD+dM) binary systems and examine the effect that a close companion has on the magnetic field generation in M dwarfs. We use a base sample of 1602 white dwarf -- main sequence binaries from Rebassa et al. to develop a set of color cuts in GALEX, SDSS, UKIDSS, and 2MASS color space to construct a sample of 1756 WD+dM high-quality pairs from the S… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1205.6806v2-abstract-full').style.display = 'inline'; document.getElementById('1205.6806v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1205.6806v2-abstract-full" style="display: none;"> We present a study of close white dwarf and M dwarf (WD+dM) binary systems and examine the effect that a close companion has on the magnetic field generation in M dwarfs. We use a base sample of 1602 white dwarf -- main sequence binaries from Rebassa et al. to develop a set of color cuts in GALEX, SDSS, UKIDSS, and 2MASS color space to construct a sample of 1756 WD+dM high-quality pairs from the SDSS DR8 spectroscopic database. We separate the individual WD and dM from each spectrum using an iterative technique that compares the WD and dM components to best-fit templates. Using the absolute height above the Galactic plane as a proxy for age, and the H伪 emission line as an indicator for magnetic activity, we investigate the age-activity relation for our sample for spectral types \leqM7. Our results show that early-type M dwarfs (\leqM4) in close binary systems are more likely to be active and have longer activity lifetimes compared to their field counterparts. However, at a spectral type of M5 (just past the onset of full convection in M dwarfs), the activity fraction and lifetimes of WD+dM binary systems becomes more comparable to that of the field M dwarfs. One of the implications of having a close binary companion is presumed to be increased stellar rotation through disk-disruption, tidal effects, or angular momentum exchange. Thus, we interpret the similarity in activity behavior between late-type dMs in WD+dM pairs and late-type field dMs to be due to a decrease in sensitivity in close binary companions (or stellar rotation), which has implications for the nature of magnetic activity in fully-convective stars. (Abridged) <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1205.6806v2-abstract-full').style.display = 'none'; document.getElementById('1205.6806v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 July, 2012; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 May, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 19 figures, emulateapj style, accepted to Astronomical Journal June 28, 2012</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1204.3565">arXiv:1204.3565</a> <span> [<a href="https://arxiv.org/pdf/1204.3565">pdf</a>, <a href="https://arxiv.org/ps/1204.3565">ps</a>, <a href="https://arxiv.org/format/1204.3565">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> White dwarfs as physics laboratories: the case of axions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Althaus%2C+L">L. Althaus</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Corsico%2C+A">A. Corsico</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Salaris%2C+M">M. Salaris</a>, <a href="/search/astro-ph?searchtype=author&query=Torres%2C+S">S. Torres</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1204.3565v1-abstract-short" style="display: inline;"> White dwarfs are almost completely degenerate objects that cannot obtain energy from thermonuclear sources, so their evolution is just a gravothermal cooling process. Recent improvements in the accuracy and precision of the luminosity function and in pulsational data of variable white dwarfs suggest that they are cooling faster than expected from conventional theory. In this contribution we show t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1204.3565v1-abstract-full').style.display = 'inline'; document.getElementById('1204.3565v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1204.3565v1-abstract-full" style="display: none;"> White dwarfs are almost completely degenerate objects that cannot obtain energy from thermonuclear sources, so their evolution is just a gravothermal cooling process. Recent improvements in the accuracy and precision of the luminosity function and in pulsational data of variable white dwarfs suggest that they are cooling faster than expected from conventional theory. In this contribution we show that the inclusion of an additional cooling term due to axions able to interact with electrons with a coupling constant g_ae ~(2-7)x10^{-13} allows to fit better the observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1204.3565v1-abstract-full').style.display = 'none'; document.getElementById('1204.3565v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 April, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 1 figure. Proceedings for the 7th Patras Workshop on Axions, WIMPs and WISPs (PATRAS 2011), Mykonos, Greece, June 27 - July 1, 2011</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1201.3243">arXiv:1201.3243</a> <span> [<a href="https://arxiv.org/pdf/1201.3243">pdf</a>, <a href="https://arxiv.org/ps/1201.3243">ps</a>, <a href="https://arxiv.org/format/1201.3243">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2012.20549.x">10.1111/j.1365-2966.2012.20549.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery of the benchmark metal poor T8 dwarf BD+01 2920B </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Burningham%2C+B">B. Burningham</a>, <a href="/search/astro-ph?searchtype=author&query=Lodieu%2C+N">N. Lodieu</a>, <a href="/search/astro-ph?searchtype=author&query=Leggett%2C+S+K">S. K. Leggett</a>, <a href="/search/astro-ph?searchtype=author&query=Tinney%2C+C+G">C. G. Tinney</a>, <a href="/search/astro-ph?searchtype=author&query=van+Spaandonk%2C+L">L. van Spaandonk</a>, <a href="/search/astro-ph?searchtype=author&query=Marocco%2C+F">F. Marocco</a>, <a href="/search/astro-ph?searchtype=author&query=Smart%2C+R">R. Smart</a>, <a href="/search/astro-ph?searchtype=author&query=Gomes%2C+J">J. Gomes</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+L">L. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Lucas%2C+P+W">P. W. Lucas</a>, <a href="/search/astro-ph?searchtype=author&query=Day-Jones%2C+A+C">A. C. Day-Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Murray%2C+D+N">D. N. Murray</a>, <a href="/search/astro-ph?searchtype=author&query=Katsiyannis%2C+A+C">A. C. Katsiyannis</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Cardoso%2C+C">C. Cardoso</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+J+R+A">J. R. A. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Folkes%2C+S">S. Folkes</a>, <a href="/search/astro-ph?searchtype=author&query=Galvez-Ortiz%2C+M+C">M. C. Galvez-Ortiz</a>, <a href="/search/astro-ph?searchtype=author&query=Homeier%2C+D">D. Homeier</a>, <a href="/search/astro-ph?searchtype=author&query=Jenkins%2C+J+S">J. S. Jenkins</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+H+R+A">H. R. A. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+Z+H">Z. H. Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1201.3243v1-abstract-short" style="display: inline;"> We have searched the WISE first data release for widely separated (<10,000AU) late T dwarf companions to Hipparcos and Gliese stars. We have discovered a new binary system containing a K-band suppressed T8p dwarf WISEP J1423+0116 and the mildly metal poor ([Fe/H]=-0.38+-0.06) primary BD+01 2920 (Hip 70319), a G1 dwarf at a distance of 17.2pc. This new benchmark has Teff=680+-55K and a mass of 20-5… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1201.3243v1-abstract-full').style.display = 'inline'; document.getElementById('1201.3243v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1201.3243v1-abstract-full" style="display: none;"> We have searched the WISE first data release for widely separated (<10,000AU) late T dwarf companions to Hipparcos and Gliese stars. We have discovered a new binary system containing a K-band suppressed T8p dwarf WISEP J1423+0116 and the mildly metal poor ([Fe/H]=-0.38+-0.06) primary BD+01 2920 (Hip 70319), a G1 dwarf at a distance of 17.2pc. This new benchmark has Teff=680+-55K and a mass of 20-50 Mjup. Its spectral properties are well modelled except for known discrepancies in the Y and K bands. Based on the well determined metallicity of its companion, the properties of BD+01 2920B imply that the currently known T dwarfs are dominated by young low-mass objects. We also present an accurate proper motion for the T8.5 dwarf WISEP J075003.84+272544.8. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1201.3243v1-abstract-full').style.display = 'none'; document.getElementById('1201.3243v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 January, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">MNRAS, accepted 2012 January 12</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1105.0287">arXiv:1105.0287</a> <span> [<a href="https://arxiv.org/pdf/1105.0287">pdf</a>, <a href="https://arxiv.org/ps/1105.0287">ps</a>, <a href="https://arxiv.org/format/1105.0287">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201116775">10.1051/0004-6361/201116775 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Time evolution of high-energy emissions of low-mass stars:I. Age determination using stellar chronology with white dwarfs in wide binaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Garc%C3%A9s%2C+A">A. Garc茅s</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a>, <a href="/search/astro-ph?searchtype=author&query=Ribas%2C+I">I. Ribas</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1105.0287v1-abstract-short" style="display: inline;"> Stellar ages are extremely difficult to determine and often subject to large uncertainties, especially for field low-mass stars. We plan to carry out a calibration of the decrease in high-energy emissions of low-mass GKM stars with time, and therefore precise age determination is a key ingredient. The overall goal of our research is to study the time evolution of these high-energy emissions as an… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1105.0287v1-abstract-full').style.display = 'inline'; document.getElementById('1105.0287v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1105.0287v1-abstract-full" style="display: none;"> Stellar ages are extremely difficult to determine and often subject to large uncertainties, especially for field low-mass stars. We plan to carry out a calibration of the decrease in high-energy emissions of low-mass GKM stars with time, and therefore precise age determination is a key ingredient. The overall goal of our research is to study the time evolution of these high-energy emissions as an essential input to studing exoplanetary atmospheres. We propose to determine stellar ages with a methodology based on wide binaries. We are interested in systems composed of a low-mass star and a white dwarf (WD), where the latter serves as a stellar chronometer for the system. We aim at obtaining reliable ages for a sample of late-type stars older than 1 Gyr. We selected a sample of wide binaries composed by a DA type WD and a GKM companion. High signal-to-noise, low-resolution spectroscopic observations were obtained for most of the WD members of the sample. Atmospheric parameters were determined by fitting the spectroscopic data to appropiate WD models. The total ages of the systems were derived by using cooling sequences, an initial-final mass relationship and evolutionary tracks, to account for the progenitor life. The spectroscopic observations have allowed us to determine ages for the binary systems using WDs as cosmochronometers. We obtained reliable ages for 27 stars between 1 and 5 Gyr, which is a range where age determination becomes difficult for field objects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1105.0287v1-abstract-full').style.display = 'none'; document.getElementById('1105.0287v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 May, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 8 figures, Accepted by A\&A 2011 March 30</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1010.5408">arXiv:1010.5408</a> <span> [<a href="https://arxiv.org/pdf/1010.5408">pdf</a>, <a href="https://arxiv.org/ps/1010.5408">ps</a>, <a href="https://arxiv.org/format/1010.5408">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.3527802">10.1063/1.3527802 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Anyone out there? Galactic Halo Post-AGB stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Weston%2C+S">S. Weston</a>, <a href="/search/astro-ph?searchtype=author&query=Napiwotzki%2C+R">R. Napiwotzki</a>, <a href="/search/astro-ph?searchtype=author&query=Catal%C3%A1n%2C+S">S. Catal谩n</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1010.5408v1-abstract-short" style="display: inline;"> We present results of a survey of post-asymptotic giant branch stars (post-AGBs) at high galactic latitude. To date, few post-AGB stars are known throughout the Galaxy and the number of known members of the older populations like the galactic halo is even smaller. This study looks at the number of post-AGB stars which are produced using different synthetic population methods and compare the result… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.5408v1-abstract-full').style.display = 'inline'; document.getElementById('1010.5408v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1010.5408v1-abstract-full" style="display: none;"> We present results of a survey of post-asymptotic giant branch stars (post-AGBs) at high galactic latitude. To date, few post-AGB stars are known throughout the Galaxy and the number of known members of the older populations like the galactic halo is even smaller. This study looks at the number of post-AGB stars which are produced using different synthetic population methods and compare the results with observations. The resulting synthetic populations are compared to observational results from a complete and studied subsample from the photographic Palomar-Green (PG) survey (with high resolution spectroscopic follow-up for post-AGB candidates) and the SDSS spectroscopic database. The results show only two candidate post-AGB stars in a complete subsample of the PG survey spanning 4200 square degrees and one in the SDSS database. We discuss and explore any observational biases which may cause the result. If found to be truely representative of the halo population, one can expect the majority of Population II stars to fail to ascend the AGB and evolve through other evolutionary channels such as the extended horizontal branch. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.5408v1-abstract-full').style.display = 'none'; document.getElementById('1010.5408v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 October, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 2 figures, 1 table, Proceedings to the 17th European White Dwarf Workshop, T眉bingen</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1010.5351">arXiv:1010.5351</a> <span> [<a href="https://arxiv.org/pdf/1010.5351">pdf</a>, <a href="https://arxiv.org/ps/1010.5351">ps</a>, <a href="https://arxiv.org/format/1010.5351">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Axions and White Dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Salaris%2C+M">M. Salaris</a>, <a href="/search/astro-ph?searchtype=author&query=Torres%2C+S">S. Torres</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1010.5351v1-abstract-short" style="display: inline;"> White dwarfs are almost completely degenerate objects that cannot obtain energy from the thermonuclear sources and their evolution is just a gravothermal process of cooling. The simplicity of these objects, the fact that the physical inputs necessary to understand them are well identified, although not always well understood, and the impressive observational background about white dwarfs make them… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.5351v1-abstract-full').style.display = 'inline'; document.getElementById('1010.5351v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1010.5351v1-abstract-full" style="display: none;"> White dwarfs are almost completely degenerate objects that cannot obtain energy from the thermonuclear sources and their evolution is just a gravothermal process of cooling. The simplicity of these objects, the fact that the physical inputs necessary to understand them are well identified, although not always well understood, and the impressive observational background about white dwarfs make them the most well studied Galactic population. These characteristics allow to use them as laboratories to test new ideas of physics. In this contribution we discuss the robustness of the method and its application to the axion case. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.5351v1-abstract-full').style.display = 'none'; document.getElementById('1010.5351v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 October, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 1 figure, to appear in the Proceedings for the 6th Patras meeting on Axions, WIMPs and WISPs</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1010.5143">arXiv:1010.5143</a> <span> [<a href="https://arxiv.org/pdf/1010.5143">pdf</a>, <a href="https://arxiv.org/ps/1010.5143">ps</a>, <a href="https://arxiv.org/format/1010.5143">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.3527798">10.1063/1.3527798 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for the coolest white dwarfs in the Galaxy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Napiwotzki%2C+R">R. Napiwotzki</a>, <a href="/search/astro-ph?searchtype=author&query=Hodgkin%2C+S">S. Hodgkin</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D">D. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Hornillos%2C+D+C">D. Cristobal Hornillos</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1010.5143v1-abstract-short" style="display: inline;"> A number of so-called ultra-cool white dwarfs have been detected in different surveys so far. However, based on anecdotal evidence it is believed that most or all of these ultra-cool white dwarfs are low-mass products of binary evolution and thus not representative for the oldest white dwarfs. Their low mass causes relatively high luminosity making them the first cool white dwarfs detected in rela… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.5143v1-abstract-full').style.display = 'inline'; document.getElementById('1010.5143v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1010.5143v1-abstract-full" style="display: none;"> A number of so-called ultra-cool white dwarfs have been detected in different surveys so far. However, based on anecdotal evidence it is believed that most or all of these ultra-cool white dwarfs are low-mass products of binary evolution and thus not representative for the oldest white dwarfs. Their low mass causes relatively high luminosity making them the first cool white dwarfs detected in relatively shallow surveys. Deeper observations are needed for the oldest, high mass white dwarfs with the longest cooling times. We report results of an ongoing project that combines deep IR and optical data. This combination plus proper motion information will allow an unambiguous identification of very cool white dwarfs, since the spectral energy distributions are very different from other types of stellar objects. The atmospheric parameters that can be derived from the spectral energy distributions together with the proper motions inferred from the IR data can be used to construct the white dwarf luminosity functions for the thick disc and halo populations. From these we will be able to test the early star formation history and initial mass function of the first stellar populations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.5143v1-abstract-full').style.display = 'none'; document.getElementById('1010.5143v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 October, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 5 figures, to appear in AIP Conference Proceedings for the 17th European White Dwarf Workshop</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1008.2960">arXiv:1008.2960</a> <span> [<a href="https://arxiv.org/pdf/1008.2960">pdf</a>, <a href="https://arxiv.org/ps/1008.2960">ps</a>, <a href="https://arxiv.org/format/1008.2960">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2010.17469.x">10.1111/j.1365-2966.2010.17469.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery of a T dwarf + white dwarf binary system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Day-Jones%2C+A+C">A. C. Day-Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Pinfield%2C+D+J">D. J. Pinfield</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiz%2C+M+T">M. T. Ruiz</a>, <a href="/search/astro-ph?searchtype=author&query=Beaumont%2C+H">H. Beaumont</a>, <a href="/search/astro-ph?searchtype=author&query=Burningham%2C+B">B. Burningham</a>, <a href="/search/astro-ph?searchtype=author&query=Gallardo%2C+J">J. Gallardo</a>, <a href="/search/astro-ph?searchtype=author&query=Gianninas%2C+A">A. Gianninas</a>, <a href="/search/astro-ph?searchtype=author&query=Bergeron%2C+P">P. Bergeron</a>, <a href="/search/astro-ph?searchtype=author&query=Napiwotzki%2C+R">R. Napiwotzki</a>, <a href="/search/astro-ph?searchtype=author&query=Jenkins%2C+J+S">J. S. Jenkins</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+Z+H">Z. H. Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Murray%2C+D">D. Murray</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Gomes%2C+J">J. Gomes</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1008.2960v1-abstract-short" style="display: inline;"> We present the discovery of the first T dwarf + white dwarf binary system LSPM 1459+0857AB, confirmed through common proper motion and spectroscopy. The white dwarf is a high proper motion object from the LSPM catalogue that we confirm spectroscopically to be a relatively cool (Teff=5535+\-45K) and magnetic (B~2MG) hydrogen-rich white dwarf, with an age of at least 4.8Gyrs. The T dwarf is a recent… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1008.2960v1-abstract-full').style.display = 'inline'; document.getElementById('1008.2960v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1008.2960v1-abstract-full" style="display: none;"> We present the discovery of the first T dwarf + white dwarf binary system LSPM 1459+0857AB, confirmed through common proper motion and spectroscopy. The white dwarf is a high proper motion object from the LSPM catalogue that we confirm spectroscopically to be a relatively cool (Teff=5535+\-45K) and magnetic (B~2MG) hydrogen-rich white dwarf, with an age of at least 4.8Gyrs. The T dwarf is a recent discovery from the UKIRT Infrared Deep Sky Survey (ULAS 1459+0857), and has a spectral type of T4.5+\-0.5 and a distance in the range 43-69pc. With an age constraint (inferred from the white dwarf) of >4.8Gyrs we estimate Teff=1200-1500K and logg=5.4-5.5 for ULAS 1459+0857, making it a benchmark T dwarf with well constrained surface gravity. We also compare the T dwarf spectra with the latest LYON group atmospheric model predictions, which despite some shortcomings are in general agreement with the observed properties of ULAS 1459+0857. The separation of the binary components (16,500-26,500AU, or 365 arcseconds on the sky) is consistent with an evolved version of the more common brown dwarf + main-sequence binary systems now known, and although the system has a wide separation, it is shown to be statistically robust as a non spurious association. The observed colours of the T dwarf show that it is relatively bright in the z band compared to other T dwarfs of similar type, and further investigation is warranted to explore the possibility that this could be a more generic indicator of older T dwarfs. Future observations of this binary system will provide even stronger constraints on the T dwarf properties, and additional systems will combine to give a more comprehensively robust test of the model atmospheres in this temperature regime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1008.2960v1-abstract-full').style.display = 'none'; document.getElementById('1008.2960v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 August, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 11 figures, MNRAS accepted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1003.3561">arXiv:1003.3561</a> <span> [<a href="https://arxiv.org/pdf/1003.3561">pdf</a>, <a href="https://arxiv.org/ps/1003.3561">ps</a>, <a href="https://arxiv.org/format/1003.3561">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/714/1/384">10.1088/0004-637X/714/1/384 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evolution of the solar activity over time and effects on planetary atmospheres. II. kappa^1 Ceti, an analog of the Sun when life arose on Earth </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ribas%2C+I">I. Ribas</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mello%2C+G+F+P">G. F. Porto de Mello</a>, <a href="/search/astro-ph?searchtype=author&query=Ferreira%2C+L+D">L. D. Ferreira</a>, <a href="/search/astro-ph?searchtype=author&query=Hebrard%2C+E">E. Hebrard</a>, <a href="/search/astro-ph?searchtype=author&query=Selsis%2C+F">F. Selsis</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Garces%2C+A">A. Garces</a>, <a href="/search/astro-ph?searchtype=author&query=Nascimento%2C+J+D+d">J. D. do Nascimento Jr.</a>, <a href="/search/astro-ph?searchtype=author&query=de+Medeiros%2C+J+R">J. R. de Medeiros</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1003.3561v2-abstract-short" style="display: inline;"> The early evolution of Earth's atmosphere and the origin of life took place at a time when physical conditions at the Earth where radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectral domain, and in order to model early planetary atmospheres in detail, a knowledge of the solar radiative input is needed. We present an investigatio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1003.3561v2-abstract-full').style.display = 'inline'; document.getElementById('1003.3561v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1003.3561v2-abstract-full" style="display: none;"> The early evolution of Earth's atmosphere and the origin of life took place at a time when physical conditions at the Earth where radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectral domain, and in order to model early planetary atmospheres in detail, a knowledge of the solar radiative input is needed. We present an investigation of the atmospheric parameters, state of evolution and high-energy fluxes of the nearby star kap^1 Cet, previously thought to have properties resembling those of the early Sun. Atmospheric parameters were derived from the excitation/ionization equilibrium of Fe I and Fe II, profile fitting of Halpha and the spectral energy distribution. The UV irradiance was derived from FUSE and HST data, and the absolute chromospheric flux from the Halpha line core. From careful spectral analysis and the comparison of different methods we propose for kap^1 Cet the following atmospheric parameters: Teff = 5665+/-30 K (Halpha profile and energy distribution), log g = 4.49+/-0.05 dex (evolutionary and spectroscopic) and [Fe/H] = +0.10+/-0.05 dex (Fe II lines). The UV radiative properties of kap^1 Cet indicate that its flux is some 35% lower than the current Sun's between 210 and 300 nm, it matches the Sun's at 170 nm and increases to at least 2-7 times higher than the Sun's between 110 and 140 nm. The use of several indicators ascribes an age to kap^1 Cet in the interval ~0.4-0.8 Gyr and the analysis of the theoretical HR diagram suggests a mass ~1.04 Msun. This star is thus a very close analog of the Sun when life arose on Earth and Mars is thought to have lost its surface bodies of liquid water. Photochemical models indicate that the enhanced UV emission leads to a significant increase in photodissociation rates compared with those commonly assumed of the early Earth. Our results show that reliable calculations of the chemical composition of early planetary atmospheres need to account for the stronger solar photodissociating UV irradiation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1003.3561v2-abstract-full').style.display = 'none'; document.getElementById('1003.3561v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 March, 2010; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 March, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0812.3043">arXiv:0812.3043</a> <span> [<a href="https://arxiv.org/pdf/0812.3043">pdf</a>, <a href="https://arxiv.org/ps/0812.3043">ps</a>, <a href="https://arxiv.org/format/0812.3043">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1742-6596/172/1/012005">10.1088/1742-6596/172/1/012005 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Axions and the white dwarf luminosity function </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Torres%2C+S">S. Torres</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0812.3043v1-abstract-short" style="display: inline;"> The evolution of white dwarfs can be described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision their luminosity function, that is, the number of stars per unit volume and luminosity interval. Since the shape of the bright branch of this function is only sensitive to the average cooling rate, we use this property to check the possible exist… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.3043v1-abstract-full').style.display = 'inline'; document.getElementById('0812.3043v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0812.3043v1-abstract-full" style="display: none;"> The evolution of white dwarfs can be described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision their luminosity function, that is, the number of stars per unit volume and luminosity interval. Since the shape of the bright branch of this function is only sensitive to the average cooling rate, we use this property to check the possible existence of axions, a proposed but not yet detected weakly interacting particle. We show here that the inclusion of the axion emissivity in the evolutionary models of white dwarfs noticeably improves the agreement between the theoretical calculations and the observational white dwarf luminosity function, thus providing the first positive indication that axions could exist. Our results indicate that the best fit is obtained for m_a cos^2beta ~ 2-6 meV, where m_a is the mass of the axion and cos^2beta is a free parameter, and that values larger than 10 meV are clearly excluded. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.3043v1-abstract-full').style.display = 'none'; document.getElementById('0812.3043v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 December, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 7 figures, to appear in Journal of Physics Conference Proceedings for the 16th European White Dwarf Workshop</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J.Phys.Conf.Ser.172:012005,2009 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0812.0911">arXiv:0812.0911</a> <span> [<a href="https://arxiv.org/pdf/0812.0911">pdf</a>, <a href="https://arxiv.org/ps/0812.0911">ps</a>, <a href="https://arxiv.org/format/0812.0911">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361:20079137">10.1051/0004-6361:20079137 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> White dwarfs in the Capodimonte deep field </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Silvotti%2C+R">R. Silvotti</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Cignoni%2C+M">M. Cignoni</a>, <a href="/search/astro-ph?searchtype=author&query=Alcala%27%2C+J+M">J. M. Alcala'</a>, <a href="/search/astro-ph?searchtype=author&query=Capaccioli%2C+M">M. Capaccioli</a>, <a href="/search/astro-ph?searchtype=author&query=Grado%2C+A">A. Grado</a>, <a href="/search/astro-ph?searchtype=author&query=Pannella%2C+M">M. Pannella</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0812.0911v1-abstract-short" style="display: inline;"> In this article we describe the search for white dwarfs (WDs) in the multi-band photometric data of the Capodimonte deep field survey. The WD candidates were selected through the V-R_C vs B-V color-color diagram. For two bright objects, the WD nature has been confirmed spectroscopically, and the atmospheric parameters (Teff and logg) have been determined. We have computed synthetic stellar popul… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.0911v1-abstract-full').style.display = 'inline'; document.getElementById('0812.0911v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0812.0911v1-abstract-full" style="display: none;"> In this article we describe the search for white dwarfs (WDs) in the multi-band photometric data of the Capodimonte deep field survey. The WD candidates were selected through the V-R_C vs B-V color-color diagram. For two bright objects, the WD nature has been confirmed spectroscopically, and the atmospheric parameters (Teff and logg) have been determined. We have computed synthetic stellar population models for the observed field and the expected number of white dwarfs agrees with the observations. The possible contamination by turn-off and horizontal branch halo stars has been estimated. The quasar (QSO) contamination has been determined by comparing the number of WD candidates in different color bins with state-of-the-art models and previous observations. The WD space density is measured at different distances from the Sun. The total contamination (non-degenerate stars + QSOs) in our sample is estimated to be around 30%. This work should be considered a small experiment in view of more ambitious projects to be performed in the coming years in larger survey contexts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.0911v1-abstract-full').style.display = 'none'; document.getElementById('0812.0911v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 December, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, accepted for publication in Astronomy and Astrophysics (21/11/2008)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0806.2807">arXiv:0806.2807</a> <span> [<a href="https://arxiv.org/pdf/0806.2807">pdf</a>, <a href="https://arxiv.org/ps/0806.2807">ps</a>, <a href="https://arxiv.org/format/0806.2807">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1086/591042">10.1086/591042 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Axions and the cooling of white dwarf stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Torres%2C+S">S. Torres</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0806.2807v2-abstract-short" style="display: inline;"> White dwarfs are the end-product of the lifes of intermediate- and low-mass stars and their evolution is described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision their luminosity function, that is, the number of stars per unit volume and luminosity interval. We show here that the shape of the bright branch of this function is only sensiti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0806.2807v2-abstract-full').style.display = 'inline'; document.getElementById('0806.2807v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0806.2807v2-abstract-full" style="display: none;"> White dwarfs are the end-product of the lifes of intermediate- and low-mass stars and their evolution is described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision their luminosity function, that is, the number of stars per unit volume and luminosity interval. We show here that the shape of the bright branch of this function is only sensitive to the averaged cooling rate of white dwarfs and we propose to use this property to check the possible existence of axions, a proposed but not yet detected weakly interacting particle. Our results indicate that the inclusion of the emission of axions in the evolutionary models of white dwarfs noticeably improves the agreement between the theoretical calculations and the observational white dwarf luminosity function. The best fit is obtained for m_a cos^2 尾~ 5 meV, where m_a is the mass of the axion and cos^2 尾is a free parameter. We also show that values larger than 10 meV are clearly excluded. The existing theoretical and observational uncertainties do not allow yet to confirm the existence of axions, but our results clearly show that if their mass is of the order of few meV, the white dwarf luminosity function is sensitive enough to detect their existence. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0806.2807v2-abstract-full').style.display = 'none'; document.getElementById('0806.2807v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 January, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 June, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 4 figures, replaced with version accepted by The Astrophysical Journal Letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophys.J.L. 682 (2008) L109 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0804.3034">arXiv:0804.3034</a> <span> [<a href="https://arxiv.org/pdf/0804.3034">pdf</a>, <a href="https://arxiv.org/ps/0804.3034">ps</a>, <a href="https://arxiv.org/format/0804.3034">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2008.13356.x">10.1111/j.1365-2966.2008.13356.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The initial-final mass relationship of white dwarfs revisited: effect on the luminosity function and mass distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Ribas%2C+I">I. Ribas</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0804.3034v1-abstract-short" style="display: inline;"> The initial-final mass relationship connects the mass of a white dwarf with the mass of its progenitor in the main-sequence. Although this function is of fundamental importance to several fields in modern astrophysics, it is not well constrained either from the theoretical or the observational points of view. In this work we revise the present semi-empirical initial-final mass relationship by re… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0804.3034v1-abstract-full').style.display = 'inline'; document.getElementById('0804.3034v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0804.3034v1-abstract-full" style="display: none;"> The initial-final mass relationship connects the mass of a white dwarf with the mass of its progenitor in the main-sequence. Although this function is of fundamental importance to several fields in modern astrophysics, it is not well constrained either from the theoretical or the observational points of view. In this work we revise the present semi-empirical initial-final mass relationship by re-evaluating the available data. The distribution obtained from grouping all our results presents a considerable dispersion, which is larger than the uncertainties. We have carried out a weighted least-squares linear fit of these data and a careful analysis to give some clues on the dependence of this relationship on some parameters such as metallicity or rotation. The semi-empirical initial-final mass relationship arising from our study covers the range of initial masses from 1.0 to 6.5 M_sun, including in this way the low-mass domain, poorly studied until recently. Finally, we have also performed a test of the initial-final mass relationship by studying its effect on the luminosity function and on the mass distribution of white dwarfs. This was done by using different initial-final mass relationships from the literature, including the expression derived in this work, and comparing the results obtained with the observational data from the Palomar Green Survey and the Sloan Digital Sky Survey (SDSS). We find that the semi-empirical initial-final mass relationship derived here gives results in good agreement with the observational data, especially in the case of the white dwarf mass distribution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0804.3034v1-abstract-full').style.display = 'none'; document.getElementById('0804.3034v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 April, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 10 figures, accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0710.3999">arXiv:0710.3999</a> <span> [<a href="https://arxiv.org/pdf/0710.3999">pdf</a>, <a href="https://arxiv.org/ps/0710.3999">ps</a>, <a href="https://arxiv.org/format/0710.3999">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361:20078230">10.1051/0004-6361:20078230 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> WD0433+270: an old Hyades stream member or an Fe-core white dwarf? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Ribas%2C+I">I. Ribas</a>, <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0710.3999v1-abstract-short" style="display: inline;"> G39-27/289 is a common proper motion pair formed by a white dwarf (WD0433+270) and a main-sequence star (BD+26 730) that apparently has been classified as a member of the Hyades open cluster. Previous studies of the white dwarf component yielded a cooling time of ~4 Gyr. Although it has not been pointed out before explicitly, this result is 6 times larger than the age of the Hyades cluster, givi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0710.3999v1-abstract-full').style.display = 'inline'; document.getElementById('0710.3999v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0710.3999v1-abstract-full" style="display: none;"> G39-27/289 is a common proper motion pair formed by a white dwarf (WD0433+270) and a main-sequence star (BD+26 730) that apparently has been classified as a member of the Hyades open cluster. Previous studies of the white dwarf component yielded a cooling time of ~4 Gyr. Although it has not been pointed out before explicitly, this result is 6 times larger than the age of the Hyades cluster, giving rise to an apparent conflict between the physics of white dwarfs and cluster main-sequence fitting. We investigate whether this system belongs to the Hyades cluster and, accordingly, give a plausible explanation to the nature of the white dwarf member. From kinematic and chemical composition considerations we believe that the system was a former member of the Hyades cluster and therefore has an evolutionary link with it. However, the evidence is not conclusive. With regards to the nature of the white dwarf component, we find that two core compositions (C/O and Fe) are compatible with the observed effective temperature and radius. These compositions yield very different cooling times of ~4 Gyr and ~1 Gyr, respectively. We distinguish two posssible scenarios. If the pair does not belong to the Hyades cluster but only to the Hyades stream, this would indicate that such stream contains rather old objects and definitely not coeval with the cluster. This has interesting consequences for Galactic dynamics. On the contrary, if the white dwarf has an Fe core, it will have a cooling time compatible with the Hyades age. This is a tantalizing result that would have implications for the thermonuclear explosion of white dwarfs and explosion theories of degenerate nuclei. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0710.3999v1-abstract-full').style.display = 'none'; document.getElementById('0710.3999v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 October, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2007. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 2 figures, accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PoSSUPERNOVA:009,2007 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0710.1542">arXiv:0710.1542</a> <span> [<a href="https://arxiv.org/pdf/0710.1542">pdf</a>, <a href="https://arxiv.org/ps/0710.1542">ps</a>, <a href="https://arxiv.org/format/0710.1542">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361:20078111">10.1051/0004-6361:20078111 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The initial-final mass relationship from white dwarfs in common proper motion pairs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+S">S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Isern%2C+J">J. Isern</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Berro%2C+E">E. Garcia-Berro</a>, <a href="/search/astro-ph?searchtype=author&query=Ribas%2C+I">I. Ribas</a>, <a href="/search/astro-ph?searchtype=author&query=Prieto%2C+C+A">C. Allende Prieto</a>, <a href="/search/astro-ph?searchtype=author&query=Bonanos%2C+A+Z">A. Z. Bonanos</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0710.1542v1-abstract-short" style="display: inline;"> The initial-final mass relationship of white dwarfs, which is poorly constrained, is of paramount importance for different aspects in modern astrophysics. From an observational perspective, most of the studies up to now have been done using white dwarfs in open clusters. In order to improve the initial-final mass relationship we explore the possibility of deriving a semi-empirical relation study… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0710.1542v1-abstract-full').style.display = 'inline'; document.getElementById('0710.1542v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0710.1542v1-abstract-full" style="display: none;"> The initial-final mass relationship of white dwarfs, which is poorly constrained, is of paramount importance for different aspects in modern astrophysics. From an observational perspective, most of the studies up to now have been done using white dwarfs in open clusters. In order to improve the initial-final mass relationship we explore the possibility of deriving a semi-empirical relation studying white dwarfs in common proper motion pairs. We have acquired long-slit spectra of the white dwarf members of the selected common proper motion pairs, as well as high resolution spectra of their companions. From these observations, a full analysis of the two members of each common proper motion pair has lead to the initial and final masses of the white dwarfs. These observations have allowed us to provide updated information for the white dwarfs, since some of them were misclassified. This work is the first one in using common proper motion pairs to improve the initial-final mass relationship, and has also allowed to cover the poorly explored low-mass domain. As in the case of studies based on white dwarfs in open clusters, the distribution of the semi-empirical data presents a large scatter, which is higher than the expected uncertainties in the derived values. This suggests that the initial-final mass relationship may not be a single-valued function. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0710.1542v1-abstract-full').style.display = 'none'; document.getElementById('0710.1542v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 October, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2007. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 5 figures, accepted for publication in A&A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0207438">arXiv:astro-ph/0207438</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0207438">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0207438">ps</a>, <a href="https://arxiv.org/format/astro-ph/0207438">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1046/j.1365-8711.2002.05880.x">10.1046/j.1365-8711.2002.05880.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cyclical period changes in Z Chamaeleontis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Baptista%2C+R">R. Baptista</a>, <a href="/search/astro-ph?searchtype=author&query=Jablonski%2C+F">F. Jablonski</a>, <a href="/search/astro-ph?searchtype=author&query=Oliveira%2C+E">E. Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Vrielmann%2C+S">S. Vrielmann</a>, <a href="/search/astro-ph?searchtype=author&query=Woudt%2C+P+A">P. A. Woudt</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+M+S">M. S. Catalan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="astro-ph/0207438v1-abstract-short" style="display: inline;"> We report the identification of cyclical changes in the orbital period of the eclipsing dwarf nova Z Cha. We used times of mid-eclipse collected from the literature and our new eclipse timings to construct an observed-minus-calculated diagram covering 30 years of observations (1972-2002). The data present cyclical variations that can be fitted by a linear plus sinusoidal function with period 28+… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0207438v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0207438v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0207438v1-abstract-full" style="display: none;"> We report the identification of cyclical changes in the orbital period of the eclipsing dwarf nova Z Cha. We used times of mid-eclipse collected from the literature and our new eclipse timings to construct an observed-minus-calculated diagram covering 30 years of observations (1972-2002). The data present cyclical variations that can be fitted by a linear plus sinusoidal function with period 28+/-2 yr and amplitude 1.0+/-0.2 minute. The statistical significance of this period by an F-test is larger than 99.9%. The derived fractional period change, Delta P/P= 4.4 x 10^{-7}, is comparable to that of other short-period cataclysmic variables (CVs), but is one order of magnitude smaller than those of the long-period CVs. Separate fits to the first and second half of the data lead to ephemerides with quite different cycle periods and amplitudes, indicating that the variation is not sinusoidal or, most probably, is not strictly periodic. The observed cyclical period change is possibly caused by a solar-type magnetic activity cycle in the secondary star. An incremental variation in the Roche lobe of the secondary star of Delta R_{L2}/R_{L2} = 1.7 x 10^{-4} is required in order to explain both the observed period change and the modulation of the quiescent brightness previously reported by Ak, Ozkan & Mattei. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0207438v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0207438v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 July, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2002. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 1 postscript figure, coded with MNRAS latex style file. To appear in Monthly Notices of the Royal Astronomical Society</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> UFSC-02-4 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Mon.Not.Roy.Astron.Soc. 335 (2002) L75 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0012488">arXiv:astro-ph/0012488</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0012488">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0012488">ps</a>, <a href="https://arxiv.org/format/astro-ph/0012488">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1046/j.1365-8711.2001.04320.x">10.1046/j.1365-8711.2001.04320.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Changes in the structure of the accretion disc of EX Draconis through the outburst cycle </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Baptista%2C+R">Raymundo Baptista</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+M+S">M. S. Catalan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="astro-ph/0012488v1-abstract-short" style="display: inline;"> (Abridged) We report on the analysis of high-speed photometry of the dwarf nova EX Dra through its outburst cycle with eclipse mapping techniques. The eclipse maps show evidence of the formation of a one-armed spiral structure in the disc at the early stages of the outburst and reveal how the disc expands during the rise until it fills most of the primary Roche lobe at maximum light. The eclipse… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0012488v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0012488v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0012488v1-abstract-full" style="display: none;"> (Abridged) We report on the analysis of high-speed photometry of the dwarf nova EX Dra through its outburst cycle with eclipse mapping techniques. The eclipse maps show evidence of the formation of a one-armed spiral structure in the disc at the early stages of the outburst and reveal how the disc expands during the rise until it fills most of the primary Roche lobe at maximum light. The eclipse maps also suggest the presence of an inward and an outward-moving heating wave during the rise and an inward-moving cooling wave in the decline. Our results suggest a systematic deceleration of both the heating and the cooling waves as they travel across the disc, in agreement with predictions of the disc instability model. The analysis of the brightness temperature profiles indicates that most of the disc appears to be in steady-state during quiescence and at outburst maximum, but not during the intermediate stages. As a general trend, the mass accretion rate in the outer regions is larger than in the inner disc on the rising branch, while the opposite holds during the decline branch. We estimate a mass accretion rate of Mdot= 10^{-8} Msun/yr at outburst maximum and Mdot= 10^{-9.1} Msun/yr in quiescence. The brightness temperature profile in quiescence also suggests that the viscosity parameter is high at this stage which favours the mass-transfer instability model. The uneclipsed light has a steady component, understood in terms of emission from the red secondary star, and a variable component that is proportional to the out of eclipse flux and corresponds to about 3 per cent of the total brightness of the system. The variable component is interpreted as arising in a disc wind. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0012488v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0012488v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 December, 2000; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2000. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in Mon. Not. R. Ast. Soc., 14 pages, 9 figures, coded with MNRAS latex style</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> UFSC-00-6 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Mon.Not.Roy.Astron.Soc. 324 (2001) 599 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0006416">arXiv:astro-ph/0006416</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0006416">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0006416">ps</a>, <a href="https://arxiv.org/format/astro-ph/0006416">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1086/312834">10.1086/312834 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A spiral structure in the disk of EX Draconis on the rise to outburst maximum </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Baptista%2C+R">Raymundo Baptista</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+M+S">M. S. Catalan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="astro-ph/0006416v1-abstract-short" style="display: inline;"> We report on the R-band eclipse mapping analysis of high-speed photometry of the dwarf nova EX Dra on the rise to the maximum of the November 1995 outburst. The eclipse map shows a one-armed spiral structure of ~180 degrees in azimuth, extending in radius from R ~0.2 to 0.43 R_{L1} (where R_{L1} is the distance from the disk center to the inner Lagrangian point), that contributes about 22 per ce… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0006416v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0006416v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0006416v1-abstract-full" style="display: none;"> We report on the R-band eclipse mapping analysis of high-speed photometry of the dwarf nova EX Dra on the rise to the maximum of the November 1995 outburst. The eclipse map shows a one-armed spiral structure of ~180 degrees in azimuth, extending in radius from R ~0.2 to 0.43 R_{L1} (where R_{L1} is the distance from the disk center to the inner Lagrangian point), that contributes about 22 per cent of the total flux of the eclipse map. The spiral structure is stationary in a reference frame co-rotating with the binary and is stable for a timescale of at least 5 binary orbits. The comparison of the eclipse maps on the rise and in quiescence suggests that the outbursts of EX Dra may be driven by episodes of enhanced mass-transfer from the secondary star. Possible explanations for the nature of the spiral structure are discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0006416v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0006416v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2000; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2000. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in the Astrophysical Journal Letters; 8 pages, 2 figures; coded with AAS latex style</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> UFSC-00-4 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophys.J. 539 (2000) L55-L58 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0002382">arXiv:astro-ph/0002382</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0002382">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0002382">ps</a>, <a href="https://arxiv.org/format/astro-ph/0002382">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1046/j.1365-8711.2000.03557.x">10.1046/j.1365-8711.2000.03557.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Eclipse studies of the dwarf-nova Ex Draconis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Baptista%2C+R">R. Baptista</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+M+S">M. S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Costa%2C+L">L. Costa</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="astro-ph/0002382v1-abstract-short" style="display: inline;"> We report on high speed photometry of EX Dra in quiescence and in outburst. The analysis of the lightcurves indicates that the outbursts do not start in the outer disc regions. The disc expands during rise to maximum and shrinks during decline and along the quiescent period. At the end of two outbursts the system was seen to go through a phase of lower brightness, characterized by an out-of-ecli… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0002382v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0002382v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0002382v1-abstract-full" style="display: none;"> We report on high speed photometry of EX Dra in quiescence and in outburst. The analysis of the lightcurves indicates that the outbursts do not start in the outer disc regions. The disc expands during rise to maximum and shrinks during decline and along the quiescent period. At the end of two outbursts the system was seen to go through a phase of lower brightness, characterized by an out-of-eclipse level ~15 per cent lower than the typical quiescent level and by the fairly symmetric eclipse of a compact source at disc centre with little evidence of a bright spot at disc rim. New eclipse timings were measured and a revised ephemeris was derived. The residuals with respect to the linear ephemeris are well described by a sinusoid of amplitude 1.2 minutes and period \~4 years and are possibly related to a solar-like magnetic activity cycle in the secondary star. Eclipse phases of the compact central source and of the bright spot were used to derive the geometry of the binary. By constraining the gas stream trajectory to pass through the observed position of the bright spot we find q=0.72+/-0.06 and i= 85 +3/-2 degrees. The binary parameters were estimated by combining the measured mass ratio with the assumption that the secondary star obeys an empirical main sequence mass-radius relation. We find M_1= 0.75+/-0.15 M_sun and M_2= 0.54+/-0.10 M_sun. The white dwarf at disc centre is surrounded by an extended and variable atmosphere or boundary layer of at least 3 times its radius and a temperature of T ~28000 K. The fluxes at mid-eclipse yield an upper limit to the contribution of the secondary star and lead to a lower limit photometric parallax distance of D= 290+/-80 pc. The fluxes of the secondary star are well matched by those of a M0+/-2 main sequence star. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0002382v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0002382v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 February, 2000; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2000. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">submitted to MNRAS, 12 pages, 9 figures; coded with MNRAS latex style</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> UFSC-00-3 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Mon.Not.Roy.Astron.Soc. 316 (2000) 529-539 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/9911141">arXiv:astro-ph/9911141</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/9911141">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/9911141">ps</a>, <a href="https://arxiv.org/format/astro-ph/9911141">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1046/j.1365-8711.2000.03240.x">10.1046/j.1365-8711.2000.03240.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-epoch Doppler tomography and polarimetry of QQ Vul </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schwope%2C+A+D">A. D. Schwope</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+M+S">Maria S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Beuermann%2C+K">Klaus Beuermann</a>, <a href="/search/astro-ph?searchtype=author&query=Metzner%2C+A">Andre Metzner</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+R+C">Robert Connon Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Steeghs%2C+D">Danny Steeghs</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="astro-ph/9911141v1-abstract-short" style="display: inline;"> (abridged abstract) We present multi-epoch high-resolution spectroscopy and photoelectric polarimetry of the long-period polar (AM Herculis star) QQ Vul. The blue emission lines show several distinct components, the sharpest of which can unequivocally be assigned to the illuminated hemisphere of the secondary star and used to trace its orbital motion. This narrow emission line can be used in com… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/9911141v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/9911141v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/9911141v1-abstract-full" style="display: none;"> (abridged abstract) We present multi-epoch high-resolution spectroscopy and photoelectric polarimetry of the long-period polar (AM Herculis star) QQ Vul. The blue emission lines show several distinct components, the sharpest of which can unequivocally be assigned to the illuminated hemisphere of the secondary star and used to trace its orbital motion. This narrow emission line can be used in combination with NaI-absorption lines from the photosphere of the companion to build a stable long-term ephemeris for the star: inferior conjunction of the companion occurs at HJD = 2448446.4710(5) + E 0.15452011(11). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/9911141v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/9911141v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 November, 1999; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 1999. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">MNRAS, in press (15 pages), see also http://www.aip.de/~preprint/preprints/1999/1999_049.html and http://www.aip.de/~preprint/preprints/1999/1999_048.html</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> AIP 99-48 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/9907144">arXiv:astro-ph/9907144</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/9907144">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/9907144">ps</a>, <a href="https://arxiv.org/format/astro-ph/9907144">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1046/j.1365-8711.1999.03001.x">10.1046/j.1365-8711.1999.03001.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The ``Outside-In'' Outburst of HT Cassiopeiae </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ioannou%2C+Z">Zach Ioannou</a>, <a href="/search/astro-ph?searchtype=author&query=Naylor%2C+T">T. Naylor</a>, <a href="/search/astro-ph?searchtype=author&query=Welsh%2C+W+F">W. F. Welsh</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+M+S">M. S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Worraker%2C+W+J">W. J. Worraker</a>, <a href="/search/astro-ph?searchtype=author&query=James%2C+N+D">N. D. James</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="astro-ph/9907144v1-abstract-short" style="display: inline;"> We present results from photometric observations of the dwarf nova system HT Cas during the eruption of November 1995. The data include the first two--colour observations of an eclipse on the rise to outburst. They show that during the rise to outburst the disc deviates significantly from steady state models, but the inclusion of an inner-disc truncation radius of about 4 $R_{wd}$ and a ``flared… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/9907144v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/9907144v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/9907144v1-abstract-full" style="display: none;"> We present results from photometric observations of the dwarf nova system HT Cas during the eruption of November 1995. The data include the first two--colour observations of an eclipse on the rise to outburst. They show that during the rise to outburst the disc deviates significantly from steady state models, but the inclusion of an inner-disc truncation radius of about 4 $R_{wd}$ and a ``flared'' disc of semi-opening angle of $10^{\circ}$ produces acceptable fits. The disc is found to have expanded at the start of the outburst to about $0.41R_{L1}$, as compared to quiescent measurements. The accretion disc then gradually decreases in radius reaching $<0.32R_{L1}$ during the last stages of the eruption. Quiescent eclipses were also observed prior to and after the eruption and a revised ephemeris is calculated. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/9907144v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/9907144v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 July, 1999; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 1999. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 11 figures, to appear in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/9905096">arXiv:astro-ph/9905096</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/9905096">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/9905096">ps</a>, <a href="https://arxiv.org/format/astro-ph/9905096">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> </div> <p class="title is-5 mathjax"> Changes in the structure of the accretion disc of HS1804+67 through the outburst cycle </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Baptista%2C+R">Raymundo Baptista</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+M+S">M. S. Catalan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="astro-ph/9905096v1-abstract-short" style="display: inline;"> We report on the analysis of high-speed photometry of the dwarf-nova HS1804+67 through its outburst cycle with eclipse mapping techniques. Eclipse maps show evidences of the formation of a spiral structure in the disc at the early stages of the outburst and reveal how the disc expands during the rise until its fills most of the primary Roche lobe at maximum light. During the decline phase, the d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/9905096v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/9905096v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/9905096v1-abstract-full" style="display: none;"> We report on the analysis of high-speed photometry of the dwarf-nova HS1804+67 through its outburst cycle with eclipse mapping techniques. Eclipse maps show evidences of the formation of a spiral structure in the disc at the early stages of the outburst and reveal how the disc expands during the rise until its fills most of the primary Roche lobe at maximum light. During the decline phase, the disc becomes progressively fainter as the cooling front moves inwards from the outer regions, until only a small bright region around the white dwarf is left at minimum light. The variable part of the uneclipsed light is possibly due to emission in a wind emanating from the inner parts of the disc. The emission from this region is sensitive to the mass accretion rate. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/9905096v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/9905096v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 May, 1999; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 1999. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 3 postscript figures, latex file, to appear in "Cataclysmic Variables: a 60th Birthday Symposium in Honour of Brian Warner", eds. P. Charles et al, New Astronomy Reviews</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/9806157">arXiv:astro-ph/9806157</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/9806157">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/9806157">ps</a>, <a href="https://arxiv.org/format/astro-ph/9806157">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1046/j.1365-8711.1998.01887.x">10.1046/j.1365-8711.1998.01887.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HST and ground-based eclipse observations of V2051 Ophiuchi: Binary parameters </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Baptista%2C+R">Raymundo Baptista</a>, <a href="/search/astro-ph?searchtype=author&query=Catalan%2C+M+S">M. S. Catalan</a>, <a href="/search/astro-ph?searchtype=author&query=Horne%2C+K">Keith Horne</a>, <a href="/search/astro-ph?searchtype=author&query=Zilli%2C+D">D. Zilli</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="astro-ph/9806157v2-abstract-short" style="display: inline;"> We report on high-speed eclipse photometry of the dwarf nova V2051 Oph while it was in a low brightness state, at B ~ 16.2 mag. In comparison to the average IUE spectra, the ultraviolet continuum and emission lines appear reduced by factors of, respectively, ~4 and ~5. Flickering activity is mostly suppressed and the lightcurve shows the eclipse of a compact white dwarf at disc centre which cont… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/9806157v2-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/9806157v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/9806157v2-abstract-full" style="display: none;"> We report on high-speed eclipse photometry of the dwarf nova V2051 Oph while it was in a low brightness state, at B ~ 16.2 mag. In comparison to the average IUE spectra, the ultraviolet continuum and emission lines appear reduced by factors of, respectively, ~4 and ~5. Flickering activity is mostly suppressed and the lightcurve shows the eclipse of a compact white dwarf at disc centre which contributes ~60 per cent of the total light at 3900--4300 A. We use measurements of contact phases in the eclipse lightcurve to derive the binary geometry and to estimate masses and relevant dimensions. We find a mass ratio of q= 0.19+/-0.03 and an inclination of i= 83+/-2 degrees. The masses of the component stars are M_1 = 0.78+/-0.06 M_dot and M_2 = 0.15+/-0.03 M_dot. Our photometric model predicts K_1 = 83+/-12 km/s and K_2= 435+/-11 km/s. The predicted value of K_1 is in accordance with the velocity amplitude obtained from the emission lines after a correction for asymmetric line emission in the disc is made (Watts et al. 1986). The secondary of V2051 Oph is significantly more massive than the secondaries of the other ultra-short period dwarf novae. V2051 Oph is probably a relatively young system, whose secondary star had not enough time to evolve out of thermal equilibrium. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/9806157v2-abstract-full').style.display = 'none'; document.getElementById('astro-ph/9806157v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 July, 1998; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 June, 1998; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 1998. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 7 postscript figures, coded using MNRAS latex style. To appear in Monthly Notices of the Royal Astronomical Society. Revised version with changes in section 4.3. For related papers and files see ftp://fsc01.fsc.ufsc.br/pub/bap and http://www.fsc.ufsc.br/~astro</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> AST-98-B02 </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 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