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class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1102.0766">arXiv:1102.0766</a> <span> [<a href="https://arxiv.org/pdf/1102.0766">pdf</a>, <a href="https://arxiv.org/ps/1102.0766">ps</a>, <a href="https://arxiv.org/format/1102.0766">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/10.1051/0004-6361/201016114">10.1051/0004-6361/201016114 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Rotating Massive Main-Sequence Stars II: Simulating a Population of LMC early B-type Stars as a Test of Rotational Mixing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Brott%2C+I">Ines Brott</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">Chris J. Evans</a>, <a href="/search/?searchtype=author&query=Hunter%2C+I">Ian Hunter</a>, <a href="/search/?searchtype=author&query=de+Koter%2C+A">Alex de Koter</a>, <a href="/search/?searchtype=author&query=Langer%2C+N">Norbert Langer</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">Philip L. Dufton</a>, <a href="/search/?searchtype=author&query=Cantiello%2C+M">Matteo Cantiello</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">Carrie Trundle</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">Danny J. Lennon</a>, <a href="/search/?searchtype=author&query=de+Mink%2C+S+E">Selma E. de Mink</a>, <a href="/search/?searchtype=author&query=Yoon%2C+S">Sung-Chul Yoon</a>, <a href="/search/?searchtype=author&query=Anders%2C+P">Peter Anders</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="1102.0766v2-abstract-short" style="display: inline;"> Rotational mixing in massive stars is a widely applied concept, with far reaching consequences for stellar evolution. Nitrogen surface abundances for a large and homogeneous sample of massive B-type stars in the LMC were obtained by the VLT-FLAMES Survey of Massive Stars. This sample is the first covering a broad range of projected stellar rotational velocities, with a large enough sample of high… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1102.0766v2-abstract-full').style.display = 'inline'; document.getElementById('1102.0766v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1102.0766v2-abstract-full" style="display: none;"> Rotational mixing in massive stars is a widely applied concept, with far reaching consequences for stellar evolution. Nitrogen surface abundances for a large and homogeneous sample of massive B-type stars in the LMC were obtained by the VLT-FLAMES Survey of Massive Stars. This sample is the first covering a broad range of projected stellar rotational velocities, with a large enough sample of high quality data to allow for a statistically significant analysis. We use the sample to provide the first rigorous test of the theory of rotational mixing in massive stars. We calculated a grid of stellar evolution models, using the FLAMES sample to calibrate some of the uncertain mixing processes. We developed a new population-synthesis code, which uses this grid to simulate a large population of stars with masses, ages and rotational velocity distributions consistent with those from the FLAMES sample. The synthesized population is then filtered by the selection effects in the observed sample, to enable a direct comparison between the empirical results and theoretical predictions. Our simulations reproduce the fraction of stars without significant nitrogen enrichment. The predicted number of rapid rotators with enhanced nitrogen is about twice as large as found observationally. Furthermore, a group of stars consisting of slowly rotating, nitrogen-enriched objects and another consisting of rapidly rotating un-enriched objects can not be reproduced by our single-star population synthesis. Additional physical processes appear to be required to understand the population of massive main-sequence stars from the FLAMES sample.We discuss the possible role of binary stars and magnetic fields in the interpretation of our results. We find that the population of slowly rotating nitrogen-enriched stars is unlikely produced via mass transfer and subsequent tidal spin-down in close binary systems <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1102.0766v2-abstract-full').style.display = 'none'; document.getElementById('1102.0766v2-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 April, 2011; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 February, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">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/1102.0530">arXiv:1102.0530</a> <span> [<a href="https://arxiv.org/pdf/1102.0530">pdf</a>, <a href="https://arxiv.org/ps/1102.0530">ps</a>, <a href="https://arxiv.org/format/1102.0530">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/10.1051/0004-6361/201016113">10.1051/0004-6361/201016113 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Brott%2C+I">Ines Brott</a>, <a href="/search/?searchtype=author&query=de+Mink%2C+S+E">Selma E. de Mink</a>, <a href="/search/?searchtype=author&query=Cantiello%2C+M">Matteo Cantiello</a>, <a href="/search/?searchtype=author&query=Langer%2C+N">Norbert Langer</a>, <a href="/search/?searchtype=author&query=de+Koter%2C+A">Alex de Koter</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">Chris J. Evans</a>, <a href="/search/?searchtype=author&query=Hunter%2C+I">Ian Hunter</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">Carrie Trundle</a>, <a href="/search/?searchtype=author&query=Vink%2C+J+S">Jorick S. Vink</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="1102.0530v2-abstract-short" style="display: inline;"> We present a dense grid of evolutionary tracks and isochrones of rotating massive main-sequence stars. We provide three grids with different initial compositions tailored to compare with early OB stars in the Small and Large Magellanic Clouds and in the Galaxy. Each grid covers masses ranging from 5 to 60 Msun and initial rotation rates between 0 and about 600 km/s. To calibrate our models we used… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1102.0530v2-abstract-full').style.display = 'inline'; document.getElementById('1102.0530v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1102.0530v2-abstract-full" style="display: none;"> We present a dense grid of evolutionary tracks and isochrones of rotating massive main-sequence stars. We provide three grids with different initial compositions tailored to compare with early OB stars in the Small and Large Magellanic Clouds and in the Galaxy. Each grid covers masses ranging from 5 to 60 Msun and initial rotation rates between 0 and about 600 km/s. To calibrate our models we used the results of the VLT-FLAMES Survey of Massive Stars. We determine the amount of convective overshooting by using the observed drop in rotation rates for stars with surface gravities log g < 3.2 to determine the width of the main sequence. We calibrate the efficiency of rotationally induced mixing using the nitrogen abundance determinations for B stars in the Large Magellanic cloud. We describe and provide evolutionary tracks and the evolution of the central and surface abundances. In particular, we discuss the occurrence of quasi-chemically homogeneous evolution, i.e. the severe effects of efficient mixing of the stellar interior found for the most massive fast rotators. We provide a detailed set of isochrones for rotating stars. Rotation as an initial parameter leads to a degeneracy between the age and the mass of massive main sequence stars if determined from its observed location in the Hertzsprung-Russell diagram. We show that the consideration of surface abundances can resolve this degeneracy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1102.0530v2-abstract-full').style.display = 'none'; document.getElementById('1102.0530v2-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 April, 2011; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 February, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">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/1011.0797">arXiv:1011.0797</a> <span> [<a href="https://arxiv.org/pdf/1011.0797">pdf</a>, <a href="https://arxiv.org/ps/1011.0797">ps</a>, <a href="https://arxiv.org/format/1011.0797">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</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/10.1088/0004-637X/726/1/39">10.1088/0004-637X/726/1/39 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A survey of diffuse interstellar bands in the Andromeda galaxy: optical spectroscopy of M31 OB stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Cordiner%2C+M+A">Martin A. Cordiner</a>, <a href="/search/?searchtype=author&query=Cox%2C+N+L+J">Nick L. J. Cox</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">Christopher J. Evans</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">Carrie Trundle</a>, <a href="/search/?searchtype=author&query=Smith%2C+K+T">Keith T. Smith</a>, <a href="/search/?searchtype=author&query=Sarre%2C+P+J">Peter J. Sarre</a>, <a href="/search/?searchtype=author&query=Gordon%2C+K+D">Karl D. Gordon</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="1011.0797v1-abstract-short" style="display: inline;"> We present the largest sample to-date of intermediate-resolution blue-to-red optical spectra of B-type supergiants in M31 and undertake the first survey of diffuse interstellar bands (DIBs) in this galaxy. Spectral classifications, radial velocities and interstellar reddenings are presented for 34 stars in three regions of M31. Radial velocities and equivalent widths are given for the 5780 and 628… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1011.0797v1-abstract-full').style.display = 'inline'; document.getElementById('1011.0797v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1011.0797v1-abstract-full" style="display: none;"> We present the largest sample to-date of intermediate-resolution blue-to-red optical spectra of B-type supergiants in M31 and undertake the first survey of diffuse interstellar bands (DIBs) in this galaxy. Spectral classifications, radial velocities and interstellar reddenings are presented for 34 stars in three regions of M31. Radial velocities and equivalent widths are given for the 5780 and 6283 DIBs towards 11 stars. Equivalent widths are also presented for the following DIBs detected in three sightlines in M31: 4428, 5705, 5780, 5797, 6203, 6269, 6283, 6379, 6613, 6660, and 6993. All of these M31 DIB carriers reside in clouds at radial velocities matching those of interstellar Na I and/or H I. The relationships between DIB equivalent widths and reddening (E(B-V)) are consistent with those observed in the local ISM of the Milky Way. Many of the observed sightlines show DIB strengths (per unit reddening) which lie at the upper end of the range of Galactic values. DIB strengths per unit reddening are found (with 68% confidence), to correlate with the interstellar UV radiation field strength. The strongest DIBs are observed where the interstellar UV flux is lowest. The mean Spitzer 8/24 micron emission ratio in our three fields is slightly lower than that measured in the Milky Way, but we identify no correlation between this ratio and the DIB strengths in M31. Interstellar oxygen abundances derived from the spectra of three M31 H II regions in one of the fields indicate that the average metallicity of the ISM in that region is 12 + log[O/H] = 8.54 +- 0.18, which is approximately equal to the value in the solar neighbourhood. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1011.0797v1-abstract-full').style.display = 'none'; document.getElementById('1011.0797v1-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 November, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2010. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1006.0504">arXiv:1006.0504</a> <span> [<a href="https://arxiv.org/pdf/1006.0504">pdf</a>, <a href="https://arxiv.org/ps/1006.0504">ps</a>, <a href="https://arxiv.org/format/1006.0504">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.1365-2966.2010.17142.x">10.1111/j.1365-2966.2010.17142.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiple Major Outbursts from a Restless Luminous Blue Variable in NGC 3432 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Pastorello%2C+A">A. Pastorello</a>, <a href="/search/?searchtype=author&query=Botticella%2C+M+T">M. T. Botticella</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Taubenberger%2C+S">S. Taubenberger</a>, <a href="/search/?searchtype=author&query=Mattila%2C+S">S. Mattila</a>, <a href="/search/?searchtype=author&query=Kankare%2C+E">E. Kankare</a>, <a href="/search/?searchtype=author&query=Elias-Rosa%2C+N">N. Elias-Rosa</a>, <a href="/search/?searchtype=author&query=Benetti%2C+S">S. Benetti</a>, <a href="/search/?searchtype=author&query=Duszanowicz%2C+G">G. Duszanowicz</a>, <a href="/search/?searchtype=author&query=Hermansson%2C+L">L. Hermansson</a>, <a href="/search/?searchtype=author&query=Beckman%2C+J+E">J. E. Beckman</a>, <a href="/search/?searchtype=author&query=Bufano%2C+F">F. Bufano</a>, <a href="/search/?searchtype=author&query=Fraser%2C+M">M. Fraser</a>, <a href="/search/?searchtype=author&query=Harutyunyan%2C+A">A. Harutyunyan</a>, <a href="/search/?searchtype=author&query=Navasardyan%2C+H">H. Navasardyan</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=van+Dyk%2C+S+D">S. D. van Dyk</a>, <a href="/search/?searchtype=author&query=Vink%2C+J+S">J. S. Vink</a>, <a href="/search/?searchtype=author&query=Wagner%2C+R+M">R. M. Wagner</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="1006.0504v1-abstract-short" style="display: inline;"> We present new photometric and spectroscopic observations of an unusual luminous blue variable (LBV) in NGC 3432, covering three major outbursts in October 2008, April 2009 and November 2009. Previously, this star experienced an outburst also in 2000 (known as SN 2000ch). During outbursts the star reached an absolute magnitude between -12.1 and -12.8. Its spectrum showed H, He I and Fe II lines wi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1006.0504v1-abstract-full').style.display = 'inline'; document.getElementById('1006.0504v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1006.0504v1-abstract-full" style="display: none;"> We present new photometric and spectroscopic observations of an unusual luminous blue variable (LBV) in NGC 3432, covering three major outbursts in October 2008, April 2009 and November 2009. Previously, this star experienced an outburst also in 2000 (known as SN 2000ch). During outbursts the star reached an absolute magnitude between -12.1 and -12.8. Its spectrum showed H, He I and Fe II lines with P-Cygni profiles during and soon after the eruptive phases, while only intermediate-width lines in pure emission (including He II 4686A were visible during quiescence. The fast-evolving light curve soon after the outbursts, the quasi-modulated light curve, the peak magnitude and the overall spectral properties are consistent with multiple episodes of variability of an extremely active LBV. However, the widths of the spectral lines indicate unusually high wind velocities (1500-2800 km/s), similar to those observed in Wolf-Rayet stars. Although modulated light curves are typical of LBVs during the S-Dor variability phase, the luminous maxima and the high frequency of outbursts are unexpected in S-Dor variables. Such extreme variability may be associated with repeated ejection episodes during a giant eruption of an LBV. Alternatively, it may be indicative of a high level of instability shortly preceding the core-collapse or due to interaction with a massive, binary companion. In this context, the variable in NGC 3432 shares some similarities with the famous stellar system HD 5980 in the Small Magellanic Cloud, which includes an erupting LBV and an early Wolf-Rayet star. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1006.0504v1-abstract-full').style.display = 'none'; document.getElementById('1006.0504v1-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 June, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">22 pages, 13 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/1001.5427">arXiv:1001.5427</a> <span> [<a href="https://arxiv.org/pdf/1001.5427">pdf</a>, <a href="https://arxiv.org/ps/1001.5427">ps</a>, <a href="https://arxiv.org/format/1001.5427">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</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/10.1088/2041-8205/717/1/L52">10.1088/2041-8205/717/1/L52 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> SN 2009kf : a UV bright type IIP supernova discovered with Pan-STARRS 1 and GALEX </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Botticella%2C+M+T">M. T. Botticella</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Pastorello%2C+A">A. Pastorello</a>, <a href="/search/?searchtype=author&query=Rodney%2C+S">S. Rodney</a>, <a href="/search/?searchtype=author&query=Rest%2C+A">A. Rest</a>, <a href="/search/?searchtype=author&query=Gezari%2C+S">S. Gezari</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Narayan%2C+G">G. Narayan</a>, <a href="/search/?searchtype=author&query=Huber%2C+M+E">M. E. Huber</a>, <a href="/search/?searchtype=author&query=Tonry%2C+J+L">J. L. Tonry</a>, <a href="/search/?searchtype=author&query=Young%2C+D">D. Young</a>, <a href="/search/?searchtype=author&query=Smith%2C+K">K. Smith</a>, <a href="/search/?searchtype=author&query=Bresolin%2C+F">F. Bresolin</a>, <a href="/search/?searchtype=author&query=Valenti%2C+S">S. Valenti</a>, <a href="/search/?searchtype=author&query=Kotak%2C+R">R. Kotak</a>, <a href="/search/?searchtype=author&query=Mattila%2C+S">S. Mattila</a>, <a href="/search/?searchtype=author&query=Kankare%2C+E">E. Kankare</a>, <a href="/search/?searchtype=author&query=Wood-Vasey%2C+W+M">W. M. Wood-Vasey</a>, <a href="/search/?searchtype=author&query=Riess%2C+A">A. Riess</a>, <a href="/search/?searchtype=author&query=Neill%2C+J+D">J. D. Neill</a>, <a href="/search/?searchtype=author&query=Forster%2C+K">K. Forster</a>, <a href="/search/?searchtype=author&query=Martin%2C+D+C">D. C. Martin</a>, <a href="/search/?searchtype=author&query=Stubbs%2C+C+W">C. W. Stubbs</a>, <a href="/search/?searchtype=author&query=Burgett%2C+W+S">W. S. Burgett</a>, <a href="/search/?searchtype=author&query=Chambers%2C+K+C">K. C. Chambers</a> , et al. (21 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="1001.5427v2-abstract-short" style="display: inline;"> We present photometric and spectroscopic observations of a luminous type IIP Supernova 2009kf discovered by the Pan-STARRS 1 (PS1) survey and detected also by GALEX. The SN shows a plateau in its optical and bolometric light curves, lasting approximately 70 days in the rest frame, with absolute magnitude of M_V = -18.4 mag. The P-Cygni profiles of hydrogen indicate expansion velocities of 9000km… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1001.5427v2-abstract-full').style.display = 'inline'; document.getElementById('1001.5427v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1001.5427v2-abstract-full" style="display: none;"> We present photometric and spectroscopic observations of a luminous type IIP Supernova 2009kf discovered by the Pan-STARRS 1 (PS1) survey and detected also by GALEX. The SN shows a plateau in its optical and bolometric light curves, lasting approximately 70 days in the rest frame, with absolute magnitude of M_V = -18.4 mag. The P-Cygni profiles of hydrogen indicate expansion velocities of 9000km/s at 61 days after discovery which is extremely high for a type IIP SN. SN 2009kf is also remarkably bright in the near-ultraviolet (NUV) and shows a slow evolution 10-20 days after optical discovery. The NUV and optical luminosity at these epochs can be modelled with a black-body with a hot effective temperature (T ~16,000 K) and a large radius (R ~1x10^{15} cm). The bright bolometric and NUV luminosity, the lightcurve peak and plateau duration, the high velocities and temperatures suggest that 2009kf is a type IIP SN powered by a larger than normal explosion energy. Recently discovered high-z SNe (0.7 < z < 2.3) have been assumed to be IIn SNe, with the bright UV luminosities due to the interaction of SN ejecta with a dense circumstellar medium (CSM). UV bright SNe similar to SN 2009kf could also account for these high-z events, and its absolute magnitude M_NUV = -21.5 +/- 0.5 mag suggests such SNe could be discovered out to z ~2.5 in the PS1 survey. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1001.5427v2-abstract-full').style.display = 'none'; document.getElementById('1001.5427v2-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 May, 2010; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 January, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">Accepted for publication in APJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0909.3780">arXiv:0909.3780</a> <span> [<a href="https://arxiv.org/pdf/0909.3780">pdf</a>, <a href="https://arxiv.org/ps/0909.3780">ps</a>, <a href="https://arxiv.org/format/0909.3780">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/10.1051/0004-6361/200912896">10.1051/0004-6361/200912896 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Extensive optical and near-infrared observations of the nearby, narrow-lined type Ic SN 2007gr: days 5 to 415 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hunter%2C+D+J">Deborah J. Hunter</a>, <a href="/search/?searchtype=author&query=Valenti%2C+S">Stefano Valenti</a>, <a href="/search/?searchtype=author&query=Kotak%2C+R">Rubina Kotak</a>, <a href="/search/?searchtype=author&query=Meikle%2C+P">Peter Meikle</a>, <a href="/search/?searchtype=author&query=Taubenberger%2C+S">Stefan Taubenberger</a>, <a href="/search/?searchtype=author&query=Pastorello%2C+A">Andrea Pastorello</a>, <a href="/search/?searchtype=author&query=Benetti%2C+S">Stefano Benetti</a>, <a href="/search/?searchtype=author&query=Stanishev%2C+V">Vallery Stanishev</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">Steven J. Smartt</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">Carrie Trundle</a>, <a href="/search/?searchtype=author&query=Arkharov%2C+A+A">Arkady A. Arkharov</a>, <a href="/search/?searchtype=author&query=Bufano%2C+M">Milena Bufano</a>, <a href="/search/?searchtype=author&query=Cappellaro%2C+E">Enrico Cappellaro</a>, <a href="/search/?searchtype=author&query=Di+Carlo%2C+E">Elisa Di Carlo</a>, <a href="/search/?searchtype=author&query=Dolci%2C+M">Mauro Dolci</a>, <a href="/search/?searchtype=author&query=Elias-Rosa%2C+N">Nancy Elias-Rosa</a>, <a href="/search/?searchtype=author&query=Frandsen%2C+S">Soeren Frandsen</a>, <a href="/search/?searchtype=author&query=Fynbo%2C+J+U">Johan U. Fynbo</a>, <a href="/search/?searchtype=author&query=Hopp%2C+U">Ulrich Hopp</a>, <a href="/search/?searchtype=author&query=Larionov%2C+V+M">Valeri M. Larionov</a>, <a href="/search/?searchtype=author&query=Laursen%2C+P">Peter Laursen</a>, <a href="/search/?searchtype=author&query=Mazzali%2C+P">Paolo Mazzali</a>, <a href="/search/?searchtype=author&query=Navasardyan%2C+H">Hripsime Navasardyan</a>, <a href="/search/?searchtype=author&query=Ries%2C+C">Christoph Ries</a>, <a href="/search/?searchtype=author&query=Riffeser%2C+A">Arno Riffeser</a> , et al. (4 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="0909.3780v1-abstract-short" style="display: inline;"> We present photometric and spectroscopic observations at optical and near-infrared wavelengths of the nearby type Ic SN 2007gr. These represent the most extensive data-set to date of any supernova of this sub-type, with frequent coverage from shortly after discovery to more than one year post-explosion. We deduce a rise time to B-band maximum of 11.5 \pm 2.7 days. We find a peak B-band magnitude… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.3780v1-abstract-full').style.display = 'inline'; document.getElementById('0909.3780v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0909.3780v1-abstract-full" style="display: none;"> We present photometric and spectroscopic observations at optical and near-infrared wavelengths of the nearby type Ic SN 2007gr. These represent the most extensive data-set to date of any supernova of this sub-type, with frequent coverage from shortly after discovery to more than one year post-explosion. We deduce a rise time to B-band maximum of 11.5 \pm 2.7 days. We find a peak B-band magnitude of M_B=-16.8, and light curves which are remarkably similar to the so-called 'hypernova' SN 2002ap. In contrast, the spectra of SNe 2007gr and 2002ap show marked differences, not least in their respective expansion velocities. We attribute these differences primarily to the density profiles of their progenitor stars at the time of explosion i.e. a more compact star for SN 2007gr compared to SN 2002ap. From the quasi-bolometric light curve of SN 2007gr, we estimate that 0.076 $\pm$ 0.010 Msun of 56Ni was produced in the explosion. Our near-infrared (IR) spectra clearly show the onset and disappearance of the first overtone of carbon monoxide (CO) between ~70 to 175 days relative to B-band maximum. The detection of the CO molecule implies that ionised He was not microscopically mixed within the carbon/oxygen layers. From the optical spectra, near-IR light curves, and colour evolution, we find no evidence for dust condensation in the ejecta out to about 400 days. Given the combination of unprecedented temporal coverage, and high signal-to-noise data, we suggest that SN 2007gr could be used as a template object for supernovae of this sub-class. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.3780v1-abstract-full').style.display = 'none'; document.getElementById('0909.3780v1-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 September, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2009. </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">A&A accepted; 26 pages & 16 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/0909.1652">arXiv:0909.1652</a> <span> [<a href="https://arxiv.org/pdf/0909.1652">pdf</a>, <a href="https://arxiv.org/format/0909.1652">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</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/10.1017/S1743921309990846">10.1017/S1743921309990846 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES Tarantula Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Bastian%2C+N">N. Bastian</a>, <a href="/search/?searchtype=author&query=Beletsky%2C+Y">Y. Beletsky</a>, <a href="/search/?searchtype=author&query=Brott%2C+I">I. Brott</a>, <a href="/search/?searchtype=author&query=Cantiello%2C+M">M. Cantiello</a>, <a href="/search/?searchtype=author&query=Clark%2C+J+S">J. S. Clark</a>, <a href="/search/?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/?searchtype=author&query=de+Mink%2C+S">S. de Mink</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Dunstall%2C+P">P. Dunstall</a>, <a href="/search/?searchtype=author&query=Gieles%2C+M">M. Gieles</a>, <a href="/search/?searchtype=author&query=Graefener%2C+G">G. Graefener</a>, <a href="/search/?searchtype=author&query=Henault-Brunet%2C+V">V. Henault-Brunet</a>, <a href="/search/?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/?searchtype=author&query=Howarth%2C+I+D">I. D. Howarth</a>, <a href="/search/?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Apellaniz%2C+J+M">J. Maiz Apellaniz</a>, <a href="/search/?searchtype=author&query=Markova%2C+N">N. Markova</a>, <a href="/search/?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/?searchtype=author&query=Simon-Diaz%2C+S">S. Simon-Diaz</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a> , et al. (6 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="0909.1652v1-abstract-short" style="display: inline;"> The Tarantula Survey is an ambitious ESO Large Programme that has obtained multi-epoch spectroscopy of over 1,000 massive stars in the 30 Doradus region of the Large Magellanic Cloud. Here we introduce the scientific motivations of the survey and give an overview of the observational sample. Ultimately, quantitative analysis of every star, paying particular attention to the effects of rotational… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.1652v1-abstract-full').style.display = 'inline'; document.getElementById('0909.1652v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0909.1652v1-abstract-full" style="display: none;"> The Tarantula Survey is an ambitious ESO Large Programme that has obtained multi-epoch spectroscopy of over 1,000 massive stars in the 30 Doradus region of the Large Magellanic Cloud. Here we introduce the scientific motivations of the survey and give an overview of the observational sample. Ultimately, quantitative analysis of every star, paying particular attention to the effects of rotational mixing and binarity, will be used to address fundamental questions in both stellar and cluster evolution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.1652v1-abstract-full').style.display = 'none'; document.getElementById('0909.1652v1-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 September, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2009. </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, to appear in the proceedings of IAU Symposium 266 "Star Clusters - Basic Galactic Building Blocks Throughout Time and Space", Rio de Janeiro, Brazil, August 2009</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0904.0119">arXiv:0904.0119</a> <span> [<a href="https://arxiv.org/pdf/0904.0119">pdf</a>, <a href="https://arxiv.org/ps/0904.0119">ps</a>, <a href="https://arxiv.org/format/0904.0119">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/10.1051/0004-6361/200911776">10.1051/0004-6361/200911776 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence of Asymmetry in SN 2007rt, a Type IIn Supernova </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Pastorello%2C+A">A. Pastorello</a>, <a href="/search/?searchtype=author&query=Benetti%2C+S">S. Benetti</a>, <a href="/search/?searchtype=author&query=Kotak%2C+R">R. Kotak</a>, <a href="/search/?searchtype=author&query=Valenti%2C+S">S. Valenti</a>, <a href="/search/?searchtype=author&query=Agnoletto%2C+I">I. Agnoletto</a>, <a href="/search/?searchtype=author&query=Bufano%2C+F">F. Bufano</a>, <a href="/search/?searchtype=author&query=Dolci%2C+M">M. Dolci</a>, <a href="/search/?searchtype=author&query=Elias-Rosa%2C+N">N. Elias-Rosa</a>, <a href="/search/?searchtype=author&query=Greiner%2C+T">T. Greiner</a>, <a href="/search/?searchtype=author&query=Hunter%2C+D">D. Hunter</a>, <a href="/search/?searchtype=author&query=Keenan%2C+F+P">F. P. Keenan</a>, <a href="/search/?searchtype=author&query=Lorenzi%2C+V">V. Lorenzi</a>, <a href="/search/?searchtype=author&query=Maguire%2C+K">K. Maguire</a>, <a href="/search/?searchtype=author&query=Taubenberger%2C+S">S. Taubenberger</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="0904.0119v2-abstract-short" style="display: inline;"> An optical photometric and spectroscopic analysis of the slowly-evolving Type IIn SN2007rt is presented, covering a duration of 481 days after discovery. Its earliest spectrum, taken approximately 100 days after the explosion epoch, indicates the presence of a dense circumstellar medium, with which the supernova ejecta is interacting. This is supported by the slowly-evolving light curve. A notab… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0904.0119v2-abstract-full').style.display = 'inline'; document.getElementById('0904.0119v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0904.0119v2-abstract-full" style="display: none;"> An optical photometric and spectroscopic analysis of the slowly-evolving Type IIn SN2007rt is presented, covering a duration of 481 days after discovery. Its earliest spectrum, taken approximately 100 days after the explosion epoch, indicates the presence of a dense circumstellar medium, with which the supernova ejecta is interacting. This is supported by the slowly-evolving light curve. A notable feature in the spectrum of SN 2007rt is the presence of a broad He I 5875 line, not usually detected in Type IIn supernovae. This may imply that the progenitor star has a high He/H ratio, having shed a significant portion of its hydrogen shell via mass-loss. An intermediate resolution spectrum reveals a narrow Halpha P-Cygni profile, the absorption component of which has a width of 128 km/s. This slow velocity suggests that the progenitor of SN 2007rt recently underwent mass-loss with wind speeds comparable to the lower limits of those detected in luminous blue variables. Asymmetries in the line profiles of H and He at early phases bears some resemblance to double-peaked features observed in a number of Ib/c spectra. These asymmetries may be indicative of an asymmetric or bipolar outflow or alternatively dust formation in the fast expanding ejecta. In addition, the late time spectrum, at over 240 days post-explosion, shows clear evidence for the presence of newly formed dust. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0904.0119v2-abstract-full').style.display = 'none'; document.getElementById('0904.0119v2-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> 23 May, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 April, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2009. </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 A&A on 4/2/2009. Accepted by A&A on 17/5/2009.15 pages plus 3 pages of online material</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0903.1286">arXiv:0903.1286</a> <span> [<a href="https://arxiv.org/pdf/0903.1286">pdf</a>, <a href="https://arxiv.org/ps/0903.1286">ps</a>, <a href="https://arxiv.org/format/0903.1286">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.1365-2966.2009.15082.x">10.1111/j.1365-2966.2009.15082.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> SN 2008S: an electron capture SN from a super-AGB progenitor? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Botticella%2C+M+T">M. T. Botticella</a>, <a href="/search/?searchtype=author&query=Pastorello%2C+A">A. Pastorello</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Meikle%2C+W+P+S">W. P. S. Meikle</a>, <a href="/search/?searchtype=author&query=Benetti%2C+S">S. Benetti</a>, <a href="/search/?searchtype=author&query=Kotak%2C+R">R. Kotak</a>, <a href="/search/?searchtype=author&query=Cappellaro%2C+E">E. Cappellaro</a>, <a href="/search/?searchtype=author&query=Crockett%2C+R+M">R. M. Crockett</a>, <a href="/search/?searchtype=author&query=Mattila%2C+S">S. Mattila</a>, <a href="/search/?searchtype=author&query=Sereno%2C+M">M. Sereno</a>, <a href="/search/?searchtype=author&query=Patat%2C+F">F. Patat</a>, <a href="/search/?searchtype=author&query=Tsvetkov%2C+D">D. Tsvetkov</a>, <a href="/search/?searchtype=author&query=Van+Loon%2C+J+T">J. Th. Van Loon</a>, <a href="/search/?searchtype=author&query=Abraham%2C+D">D. Abraham</a>, <a href="/search/?searchtype=author&query=Agnoletto%2C+I">I. Agnoletto</a>, <a href="/search/?searchtype=author&query=Arbour%2C+R">R. Arbour</a>, <a href="/search/?searchtype=author&query=Benn%2C+C">C. Benn</a>, <a href="/search/?searchtype=author&query=Di+Rico%2C+G">G. Di Rico</a>, <a href="/search/?searchtype=author&query=Elias-Rosa%2C+N">N. Elias-Rosa</a>, <a href="/search/?searchtype=author&query=Gorshanov%2C+D+L">D. L. Gorshanov</a>, <a href="/search/?searchtype=author&query=Harutyunyan%2C+A">A. Harutyunyan</a>, <a href="/search/?searchtype=author&query=Hunter%2C+D">D. Hunter</a>, <a href="/search/?searchtype=author&query=Lorenzi%2C+V">V. Lorenzi</a>, <a href="/search/?searchtype=author&query=Keenan%2C+F+P">F. P. Keenan</a>, <a href="/search/?searchtype=author&query=Maguire%2C+K">K. Maguire</a> , et al. (9 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="0903.1286v3-abstract-short" style="display: inline;"> We present comprehensive photometric and spectroscopic observations of the faint transient SN 2008S discovered in NGC 6946. SN 2008S exhibited slow photometric evolution and almost no spectral variability during the first nine months, implying a high density CS medium. The light curve is similar in shape to that of SN 1998S and SN 1979C, although significantly fainter at maximum light. Our quasi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0903.1286v3-abstract-full').style.display = 'inline'; document.getElementById('0903.1286v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0903.1286v3-abstract-full" style="display: none;"> We present comprehensive photometric and spectroscopic observations of the faint transient SN 2008S discovered in NGC 6946. SN 2008S exhibited slow photometric evolution and almost no spectral variability during the first nine months, implying a high density CS medium. The light curve is similar in shape to that of SN 1998S and SN 1979C, although significantly fainter at maximum light. Our quasi-bolometric lightcurve extends to 300 days and shows a tail phase decay rate consistent with that of ^{56}Co. We propose that this is evidence for an explosion and formation of ^{56}Ni (0.0015 +/- 0.0004 M_Sun). The large MIR flux detected shortly after explosion can be explained by a light echo from pre-exisiting dust. The late NIR flux excess is plausibly due to a combination of warm newly-formed ejecta dust together with shock-heated dust in the CS environment. We reassess the progenitor object detected previously in Spitzer archive images, supplementing this discussion with a model of the MIR spectral energy distribution. This supports the idea of a dusty, optically thick shell around SN 2008S with an inner radius of nearly 90AU and outer radius of 450AU, and an inferred heating source of 3000 K and luminosity of L ~ 10^{4.6} L_Sun. The combination of our monitoring data and the evidence from the progenitor analysis leads us to support the scenario of a weak electron capture supernova explosion in a super-AGB progenitor star (of initial mass 6-8 M_sun) embedded within a thick CS gaseous envelope. We suggest that all of main properties of the electron capture SN phenomenon are observed in SN 2008S and future observations may allow a definitive answer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0903.1286v3-abstract-full').style.display = 'none'; document.getElementById('0903.1286v3-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 May, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 March, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2009. </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 MNRAS (2009 May 7)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0901.3853">arXiv:0901.3853</a> <span> [<a href="https://arxiv.org/pdf/0901.3853">pdf</a>, <a href="https://arxiv.org/ps/0901.3853">ps</a>, <a href="https://arxiv.org/format/0901.3853">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/10.1051/0004-6361/200809925">10.1051/0004-6361/200809925 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</a>, <a href="/search/?searchtype=author&query=Brott%2C+I">I. Brott</a>, <a href="/search/?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Howarth%2C+I+D">I. D. Howarth</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</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="0901.3853v1-abstract-short" style="display: inline;"> We have previously analysed the spectra of 135 early B-type stars in the LMC and found several groups of stars that have chemical compositions that conflict with the theory of rotational mixing. Here we extend this study to Galactic and SMC metallicities with the analysis of ~50 Galactic and ~100 SMC early B-type stars with rotational velocities up to ~300km/s. The surface nitrogen abundances ar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0901.3853v1-abstract-full').style.display = 'inline'; document.getElementById('0901.3853v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0901.3853v1-abstract-full" style="display: none;"> We have previously analysed the spectra of 135 early B-type stars in the LMC and found several groups of stars that have chemical compositions that conflict with the theory of rotational mixing. Here we extend this study to Galactic and SMC metallicities with the analysis of ~50 Galactic and ~100 SMC early B-type stars with rotational velocities up to ~300km/s. The surface nitrogen abundances are utilised as a probe of the mixing process. In the SMC, we find a population of slowly rotating nitrogen-rich stars amongst the early B type core-hydrogen burning stars, similar to the LMC. In the Galactic sample we find no significant enrichment amongst the core hydrogen-burning stars, which appears to be in contrast with the expectation from both rotating single-star and close binary evolution models. However, only a small number of the rapidly rotating stars have evolved enough to produce a significant nitrogen enrichment, and these may be analogous to the non-enriched rapid rotators previously found in the LMC sample. Finally, in each metallicity regime, a population of highly enriched supergiants is observed, which cannot be the immediate descendants of core-hydrogen burning stars. Their abundances are, however, compatible with them having gone through a previous red supergiant phase. Together, these observations paint a complex picture of the nitrogen enrichment in massive main sequence and supergiant stellar atmospheres, where age and binarity cause crucial effects. Whether rotational mixing is required to understand our results remains an open question at this time, but could be answered by identifying the true binary fraction in those groups of stars that do not agree with single-star evolutionary models (abridged). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0901.3853v1-abstract-full').style.display = 'none'; document.getElementById('0901.3853v1-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 January, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2009. </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 paper - 86 pages with tables and 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/0807.1695">arXiv:0807.1695</a> <span> [<a href="https://arxiv.org/pdf/0807.1695">pdf</a>, <a href="https://arxiv.org/ps/0807.1695">ps</a>, <a href="https://arxiv.org/format/0807.1695">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/10.1126/science.1158088">10.1126/science.1158088 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The metamorphosis of Supernova SN2008D/XRF080109: a link between Supernovae and GRBs/Hypernovae </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Mazzali%2C+P+A">Paolo A. Mazzali</a>, <a href="/search/?searchtype=author&query=Valenti%2C+S">Stefano Valenti</a>, <a href="/search/?searchtype=author&query=Della+Valle%2C+M">Massimo Della Valle</a>, <a href="/search/?searchtype=author&query=Chincarini%2C+G">Guido Chincarini</a>, <a href="/search/?searchtype=author&query=Sauer%2C+D+N">Daniel N. Sauer</a>, <a href="/search/?searchtype=author&query=Benetti%2C+S">Stefano Benetti</a>, <a href="/search/?searchtype=author&query=Pian%2C+E">Elena Pian</a>, <a href="/search/?searchtype=author&query=Piran%2C+T">Tsvi Piran</a>, <a href="/search/?searchtype=author&query=D%27Elia%2C+V">Valerio D'Elia</a>, <a href="/search/?searchtype=author&query=Elias-Rosa%2C+N">Nancy Elias-Rosa</a>, <a href="/search/?searchtype=author&query=Margutti%2C+R">Raffaella Margutti</a>, <a href="/search/?searchtype=author&query=Pasotti%2C+F">Francesco Pasotti</a>, <a href="/search/?searchtype=author&query=Antonelli%2C+L+A">L. Angelo Antonelli</a>, <a href="/search/?searchtype=author&query=Bufano%2C+F">Filomena Bufano</a>, <a href="/search/?searchtype=author&query=Campana%2C+S">Sergio Campana</a>, <a href="/search/?searchtype=author&query=Cappellaro%2C+E">Enrico Cappellaro</a>, <a href="/search/?searchtype=author&query=Covino%2C+S">Stefano Covino</a>, <a href="/search/?searchtype=author&query=D%27Avanzo%2C+P">Paolo D'Avanzo</a>, <a href="/search/?searchtype=author&query=Fiore%2C+F">Fabrizio Fiore</a>, <a href="/search/?searchtype=author&query=Fugazza%2C+D">Dino Fugazza</a>, <a href="/search/?searchtype=author&query=Gilmozzi%2C+R">Roberto Gilmozzi</a>, <a href="/search/?searchtype=author&query=Hunter%2C+D">Deborah Hunter</a>, <a href="/search/?searchtype=author&query=Maguire%2C+K">Kate Maguire</a>, <a href="/search/?searchtype=author&query=Maiorano%2C+E">Elisabetta Maiorano</a>, <a href="/search/?searchtype=author&query=Marziani%2C+P">Paola Marziani</a> , et al. (16 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="0807.1695v1-abstract-short" style="display: inline;"> The only supernovae (SNe) to have shown early gamma-ray or X-ray emission thus far are overenergetic, broad-lined Type Ic SNe (Hypernovae - HNe). Recently, SN 2008D shows several novel features: (i) weak XRF, (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SNIc HNe, (iv) development of He lines as in SNeIb. Detailed analysis shows that SN 2008D was not a nor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0807.1695v1-abstract-full').style.display = 'inline'; document.getElementById('0807.1695v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0807.1695v1-abstract-full" style="display: none;"> The only supernovae (SNe) to have shown early gamma-ray or X-ray emission thus far are overenergetic, broad-lined Type Ic SNe (Hypernovae - HNe). Recently, SN 2008D shows several novel features: (i) weak XRF, (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SNIc HNe, (iv) development of He lines as in SNeIb. Detailed analysis shows that SN 2008D was not a normal SN: its explosion energy (KE ~ 6*10^{51} erg) and ejected mass (~7 Msun) are intermediate between normal SNeIbc and HNe. We derive that SN 2008D was originally a ~30Msun star. When it collapsed a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0807.1695v1-abstract-full').style.display = 'none'; document.getElementById('0807.1695v1-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 July, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">22 pages, 7 figures. Accepted for publication in Science</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science, 321, 1185 (2008) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0805.2953">arXiv:0805.2953</a> <span> [<a href="https://arxiv.org/pdf/0805.2953">pdf</a>, <a href="https://arxiv.org/format/0805.2953">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/10.1051/0004-6361:200809399">10.1051/0004-6361:200809399 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Araucaria Project: VLT-spectroscopy of blue massive stars in NGC 55 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Bresolin%2C+F">F. Bresolin</a>, <a href="/search/?searchtype=author&query=Gieren%2C+W">W. Gieren</a>, <a href="/search/?searchtype=author&query=Pietrzynski%2C+G">G. Pietrzynski</a>, <a href="/search/?searchtype=author&query=Kudritzki%2C+R+-">R. -P. Kudritzki</a>, <a href="/search/?searchtype=author&query=Demarco%2C+R">R. Demarco</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="0805.2953v1-abstract-short" style="display: inline;"> This is the first paper of a series devoted to studying the population of blue massive stars in NGC 55, a galaxy of the Sculptor group at a distance of about 2 Mpc. We have obtained optical (3300-6210A) low-resolution spectra of blue massive stars with VLT-FORS2, which we have classified with the aid of Milky Way and Magellanic Cloud standard stars. We have developed the first census of massiv… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0805.2953v1-abstract-full').style.display = 'inline'; document.getElementById('0805.2953v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0805.2953v1-abstract-full" style="display: none;"> This is the first paper of a series devoted to studying the population of blue massive stars in NGC 55, a galaxy of the Sculptor group at a distance of about 2 Mpc. We have obtained optical (3300-6210A) low-resolution spectra of blue massive stars with VLT-FORS2, which we have classified with the aid of Milky Way and Magellanic Cloud standard stars. We have developed the first census of massive blue stars in NGC 55. A study of stellar radial velocities shows agreement with existing HI rotational velocity curve work and reveals the presence of one object with peculiar velocity. A qualitative study of the stellar metallicity suggests that its global distribution over NGC 55 is close to that of the LMC, as derived from previous studies. We present a catalogue with 164 classifications of blue massive stars in NGC 55. This catalogue is a first and necessary step for the subsequent quantitative study of blue massive stars in NGC 55 with state-of-the-art models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0805.2953v1-abstract-full').style.display = 'none'; document.getElementById('0805.2953v1-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 May, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">42 pages, 38 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/0804.2392">arXiv:0804.2392</a> <span> [<a href="https://arxiv.org/pdf/0804.2392">pdf</a>, <a href="https://arxiv.org/ps/0804.2392">ps</a>, <a href="https://arxiv.org/format/0804.2392">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/10.1051/0004-6361:200809755">10.1051/0004-6361:200809755 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> SN 2005 gj: Evidence for LBV supernovae progenitors? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Kotak%2C+R">R. Kotak</a>, <a href="/search/?searchtype=author&query=Vink%2C+J+S">J. S. Vink</a>, <a href="/search/?searchtype=author&query=Meikle%2C+W+P+S">W. P. S. Meikle</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="0804.2392v1-abstract-short" style="display: inline;"> There has been mounting observational evidence in favour of Luminous Blue Variables (LBVs) being the direct progenitors of supernovae. Here we present possibly the most convincing evidence yet for such progenitors. We find multiple absorption component P-Cygni profiles of hydrogen and helium in the spectrum of SN 2005gj, which we interpret as being an imprint of the progenitors mass-loss history… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0804.2392v1-abstract-full').style.display = 'inline'; document.getElementById('0804.2392v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0804.2392v1-abstract-full" style="display: none;"> There has been mounting observational evidence in favour of Luminous Blue Variables (LBVs) being the direct progenitors of supernovae. Here we present possibly the most convincing evidence yet for such progenitors. We find multiple absorption component P-Cygni profiles of hydrogen and helium in the spectrum of SN 2005gj, which we interpret as being an imprint of the progenitors mass-loss history. Such profiles have previously only been detected in Luminous Blue Variables. This striking resemblance of the profiles, along with wind velocities and periods consistent with LBV's leads us to connect SN 2005gj to an LBV progenitor. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0804.2392v1-abstract-full').style.display = 'none'; document.getElementById('0804.2392v1-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 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">Accepted as a letter to A&A, 4 pages,3 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/0803.4262">arXiv:0803.4262</a> <span> [<a href="https://arxiv.org/pdf/0803.4262">pdf</a>, <a href="https://arxiv.org/ps/0803.4262">ps</a>, <a href="https://arxiv.org/format/0803.4262">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.1365-2966.2008.13347.x">10.1111/j.1365-2966.2008.13347.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The blue supergiant Sher 25 and its intriguing hourglass nebula </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hendry%2C+M+A">M. A. Hendry</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Skillman%2C+E+D">E. D. Skillman</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</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="0803.4262v1-abstract-short" style="display: inline;"> The blue supergiant Sher 25 is surrounded by an asymmetric, hourglass-shaped circumstellar nebula. Its structure and dynamics have been studied previously through high-resolution imaging and spectroscopy, and it appears dynamically similar to the ring structure around SN 1987A. Here we present long-slit spectroscopy of the circumstellar nebula around Sher 25, and of the background nebula of the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0803.4262v1-abstract-full').style.display = 'inline'; document.getElementById('0803.4262v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0803.4262v1-abstract-full" style="display: none;"> The blue supergiant Sher 25 is surrounded by an asymmetric, hourglass-shaped circumstellar nebula. Its structure and dynamics have been studied previously through high-resolution imaging and spectroscopy, and it appears dynamically similar to the ring structure around SN 1987A. Here we present long-slit spectroscopy of the circumstellar nebula around Sher 25, and of the background nebula of the host cluster NGC 3603. We perform a detailed nebular abundance analysis to measure the gas-phase abundances of oxygen, nitrogen, sulphur, neon and argon. The oxygen abundance in the circumstellar nebula (12 + log[O/H] = 8.61 +/- 0.13 dex) is similar to that in the background nebula (8.56 +/- 0.07), suggesting the composition of the host cluster is around solar. However, we confirm that the circumstellar nebula is very rich in nitrogen, with an abundance of 8.91 +/- 0.15, compared to the background value of 7.47 +/- 0.18. A new analysis of the stellar spectrum with the FASTWIND model atmosphere code suggests that the photospheric nitrogen and oxygen abundances in Sher 25 are consistent with the nebular results. While the nitrogen abundances are high, when compared to stellar evolutionary models they do not unambiguously confirm that the star has undergone convective dredge-up during a previous red supergiant phase. We suggest that the more likely scenario is that the nebula was ejected from the star while it was in the blue supergiant phase. The star's initial mass was around 50 M_sun, which is rather too high for it to have had a convective envelope stage as a red supergiant. Rotating stellar models that lead to mixing of core-processed material to the stellar surface during core H-burning can quantitatively match the stellar results with the nebula abundances. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0803.4262v1-abstract-full').style.display = 'none'; document.getElementById('0803.4262v1-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 March, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">Revised after initial referee report, to appear in MNRAS. 24 pages, some figures significantly degraded, high-res copy available at http://star.pst.qub.ac.uk/~sjs/papers/sher25/</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0803.2820">arXiv:0803.2820</a> <span> [<a href="https://arxiv.org/pdf/0803.2820">pdf</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"> The VLT-FLAMES Survey of Massive Stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/?searchtype=author&query=Mokiem%2C+M+R">M. R. Mokiem</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/?searchtype=author&query=Vink%2C+J+S">J. S. Vink</a>, <a href="/search/?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/?searchtype=author&query=Simon-Diaz%2C+S">S. Simon-Diaz</a>, <a href="/search/?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/?searchtype=author&query=Brott%2C+I">I. Brott</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="0803.2820v1-abstract-short" style="display: inline;"> The VLT-FLAMES Survey of Massive Stars was an ESO Large Programme to understand rotational mixing and stellar mass-loss in different metallicity environments, in order to better constrain massive star evolution. We gathered high-quality spectra of over 800 stars in the Galaxy and in the Magellanic Clouds. A sample of this size is unprecedented, enabled by the first high-resolution, wide-field, m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0803.2820v1-abstract-full').style.display = 'inline'; document.getElementById('0803.2820v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0803.2820v1-abstract-full" style="display: none;"> The VLT-FLAMES Survey of Massive Stars was an ESO Large Programme to understand rotational mixing and stellar mass-loss in different metallicity environments, in order to better constrain massive star evolution. We gathered high-quality spectra of over 800 stars in the Galaxy and in the Magellanic Clouds. A sample of this size is unprecedented, enabled by the first high-resolution, wide-field, multi-object spectrograph on an 8-m telescope. We developed spectral analysis techniques that, in combination with non-LTE, line-blanketed model atmospheres, were used to quantitatively characterise every star. The large sample, combined with the theoretical developments, has produced exciting new insights into the evolution of the most massive stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0803.2820v1-abstract-full').style.display = 'none'; document.getElementById('0803.2820v1-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, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">7 pages, from the March 2008 edition of The ESO Messenger (vol. 131, p25). A fully formatted version is available at: http://www.eso.org/sci/publications/messenger/</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0801.3609">arXiv:0801.3609</a> <span> [<a href="https://arxiv.org/pdf/0801.3609">pdf</a>, <a href="https://arxiv.org/ps/0801.3609">ps</a>, <a href="https://arxiv.org/format/0801.3609">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/10.1051/0004-6361:20079309">10.1051/0004-6361:20079309 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Detection of diffuse interstellar bands in M31 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Cordiner%2C+M+A">M. A. Cordiner</a>, <a href="/search/?searchtype=author&query=Cox%2C+N+L+J">N. L. J. Cox</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</a>, <a href="/search/?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/?searchtype=author&query=Bresolin%2C+F">F. Bresolin</a>, <a href="/search/?searchtype=author&query=Salama%2C+F">F. Salama</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="0801.3609v1-abstract-short" style="display: inline;"> We investigate the diffuse interstellar band (DIB) spectrum in the interstellar medium of M31. The DEIMOS spectrograph of the W. M. Keck observatory was used to make optical spectroscopic observations of two supergiant stars, MAG 63885 and MAG 70817, in the vicinity of the OB78 association in M31 where the metallicity is approximately equal to solar. The 5780, 5797, 6203, 6283 and 6613 DIBs are… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0801.3609v1-abstract-full').style.display = 'inline'; document.getElementById('0801.3609v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0801.3609v1-abstract-full" style="display: none;"> We investigate the diffuse interstellar band (DIB) spectrum in the interstellar medium of M31. The DEIMOS spectrograph of the W. M. Keck observatory was used to make optical spectroscopic observations of two supergiant stars, MAG 63885 and MAG 70817, in the vicinity of the OB78 association in M31 where the metallicity is approximately equal to solar. The 5780, 5797, 6203, 6283 and 6613 DIBs are detected in both sightlines at velocities matching the M31 interstellar Na I absorption. The spectra are classified and interstellar reddenings are derived for both stars. Diffuse interstellar band (DIB) equivalent widths and radial velocities are presented. The spectrum of DIBs observed in M31 towards MAG 63885 is found to be similar to that observed in the Milky Way. Towards MAG 70817 the DIB equivalent widths per unit reddening are about three times the Galactic average. Compared to observations elsewhere in the Universe, relative to reddening the M31 ISM in the vicinity of OB78 is apparently a highly favourable environment for the formation of DIB carriers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0801.3609v1-abstract-full').style.display = 'none'; document.getElementById('0801.3609v1-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> 23 January, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2008. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0711.2267">arXiv:0711.2267</a> <span> [<a href="https://arxiv.org/pdf/0711.2267">pdf</a>, <a href="https://arxiv.org/ps/0711.2267">ps</a>, <a href="https://arxiv.org/format/0711.2267">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/10.1086/587436">10.1086/587436 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES survey of massive stars: rotation and nitrogen enrichment as the key to understanding massive star evolution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</a>, <a href="/search/?searchtype=author&query=Brott%2C+I">I. Brott</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</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="0711.2267v2-abstract-short" style="display: inline;"> Rotation has become an important element in evolutionary models of massive stars, specifically via the prediction of rotational mixing. Here, we study a sample of stars, including rapid rotators, to constrain such models and use nitrogen enrichments as a probe of the mixing process. Chemical compositions (C, N, O, Mg and Si) have been estimated for 135 early B-type stars in the Large Magellanic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0711.2267v2-abstract-full').style.display = 'inline'; document.getElementById('0711.2267v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0711.2267v2-abstract-full" style="display: none;"> Rotation has become an important element in evolutionary models of massive stars, specifically via the prediction of rotational mixing. Here, we study a sample of stars, including rapid rotators, to constrain such models and use nitrogen enrichments as a probe of the mixing process. Chemical compositions (C, N, O, Mg and Si) have been estimated for 135 early B-type stars in the Large Magellanic Cloud with projected rotational velocities up to ~300km/s using a non-LTE TLUSTY model atmosphere grid. Evolutionary models, including rotational mixing, have been generated attempting to reproduce these observations by adjusting the overshooting and rotational mixing parameters and produce reasonable agreement with 60% of our core hydrogen burning sample. We find (excluding known binaries) a significant population of highly nitrogen enriched intrinsic slow rotators vsini less than 50km/s incompatible with our models ~20% of the sample). Furthermore, while we find fast rotators with enrichments in agreement with the models, the observation of evolved (log g less than 3.7dex) fast rotators that are relatively unenriched (a further ~20% of the sample) challenges the concept of rotational mixing. We also find that 70% of our blue supergiant sample cannot have evolved directly from the hydrogen burning main-sequence. We are left with a picture where invoking binarity and perhaps fossil magnetic fields are required to understand the surface properties of a population of massive main sequence stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0711.2267v2-abstract-full').style.display = 'none'; document.getElementById('0711.2267v2-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, 2008; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 November, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">ApJL. 10 pages, 1 figure. Updated to match accepted version</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0711.2264">arXiv:0711.2264</a> <span> [<a href="https://arxiv.org/pdf/0711.2264">pdf</a>, <a href="https://arxiv.org/ps/0711.2264">ps</a>, <a href="https://arxiv.org/format/0711.2264">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/10.1051/0004-6361:20078511">10.1051/0004-6361:20078511 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES survey of massive stars: atmospheric parameters and rotational velocity distributions for B-type stars in the Magellanic Clouds </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Simon-Diaz%2C+S">S. Simon-Diaz</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</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="0711.2264v1-abstract-short" style="display: inline;"> We provide atmospheric parameters and rotational velocities of a large sample (~400) of O- and early B-type stars, analysed in a homogeneous and consistent manner, for use in constraining theoretical models. Comparison of the rotational velocities with evolutionary tracks suggest that the end of core hydrogen burning occurs later than currently predicted. We also show that the large number of th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0711.2264v1-abstract-full').style.display = 'inline'; document.getElementById('0711.2264v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0711.2264v1-abstract-full" style="display: none;"> We provide atmospheric parameters and rotational velocities of a large sample (~400) of O- and early B-type stars, analysed in a homogeneous and consistent manner, for use in constraining theoretical models. Comparison of the rotational velocities with evolutionary tracks suggest that the end of core hydrogen burning occurs later than currently predicted. We also show that the large number of the luminous blue supergiants observed in the fields are unlikely to have directly evolved from main-sequence massive O-type stars as neither their low rotational velocities or position on the H-R diagram are predicted. We suggest that blue-loops or mass-transfer binary systems may populate the blue supergiant regime. By comparing the rotational velocity distributions of the Magellanic Cloud stars to a similar Galactic sample we find that (at 3sigma confidence level) massive stars (above 8Msun) in the SMC rotate faster than those in the solar neighbourhood. However there appears to be no significant difference between the rotational velocity distributions in the Galaxy and the LMC. We find that the vsini distributions in the SMC and LMC can modelled with an intrinsic rotational velocity distribution which is a Gaussian peaking at 175km/s (SMC) and 100km/s (LMC). We find that in NGC346 in the SMC, the 10-25Msun main-sequence stars appear to rotate faster than their higher mass counterparts. Recently Yoon et al. (2006) have determined rates of GRBs by modelling rapidly rotating massive star progenitors. Our measured rotational velocity distribution for the 10-25Msun stars is peaked at slightly higher velocities than they assume, supporting the idea that GRBs could come from rapid rotators with initial masses as low as 14Msun at low metallicities. (abridged). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0711.2264v1-abstract-full').style.display = 'none'; document.getElementById('0711.2264v1-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, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">25 pages with tables. 11 figures. Submitted to A&A and corrected for referee's comments</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0710.3252">arXiv:0710.3252</a> <span> [<a href="https://arxiv.org/pdf/0710.3252">pdf</a>, <a href="https://arxiv.org/ps/0710.3252">ps</a>, <a href="https://arxiv.org/format/0710.3252">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.1365-2966.2007.12597.x">10.1111/j.1365-2966.2007.12597.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Iron abundances from optical Fe III absorption lines in B-type stellar spectra </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Thompson%2C+H+M+A">H. M. A. Thompson</a>, <a href="/search/?searchtype=author&query=Keenan%2C+F+P">F. P. Keenan</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</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="0710.3252v1-abstract-short" style="display: inline;"> The role of optical Fe III absorption lines in B-type stars as iron abundance diagnostics is considered. To date, ultraviolet Fe lines have been widely used in B-type stars, although line blending can severely hinder their diagnostic power. Using optical spectra, covering a wavelength range ~ 3560 - 9200 A, a sample of Galactic B-type main-sequence and supergiant stars of spectral types B0.5 to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0710.3252v1-abstract-full').style.display = 'inline'; document.getElementById('0710.3252v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0710.3252v1-abstract-full" style="display: none;"> The role of optical Fe III absorption lines in B-type stars as iron abundance diagnostics is considered. To date, ultraviolet Fe lines have been widely used in B-type stars, although line blending can severely hinder their diagnostic power. Using optical spectra, covering a wavelength range ~ 3560 - 9200 A, a sample of Galactic B-type main-sequence and supergiant stars of spectral types B0.5 to B7 are investigated. A comparison of the observed Fe III spectra of supergiants, and those predicted from the model atmosphere codes TLUSTY (plane-parallel, non-LTE), with spectra generated using SYNSPEC (LTE), and CMFGEN (spherical, non-LTE), reveal that non-LTE effects appear small. In addition, a sample of main-sequence and supergiant objects, observed with FEROS, reveal LTE abundance estimates consistent with the Galactic environment and previous optical studies. Based on the present study, we list a number of Fe III transitions which we recommend for estimating the iron abundance from early B-type stellar spectra. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0710.3252v1-abstract-full').style.display = 'none'; document.getElementById('0710.3252v1-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 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">3 figures and 8 tables. Table 3 is to be published online only (included here on last page). 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/0706.1731">arXiv:0706.1731</a> <span> [<a href="https://arxiv.org/pdf/0706.1731">pdf</a>, <a href="https://arxiv.org/ps/0706.1731">ps</a>, <a href="https://arxiv.org/format/0706.1731">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/10.1051/0004-6361:20077838">10.1051/0004-6361:20077838 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES survey of massive stars: Evolution of surface N abundances and effective temperature scales in the Galaxy and Magellanic Clouds </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J Smartt</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</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="0706.1731v1-abstract-short" style="display: inline;"> We present an analysis of high resolution VLT-FLAMES spectra of 61 B-type stars with relatively narrow-lined spectra located in 4 fields centered on the Milky Way clusters; NGC3293 & NGC4755 and the Large and Small Magellanic cloud clusters; NGC2004 and NGC330. For each object a quantitative analysis was carried out using the non-LTE model atmosphere code TLUSTY; resulting in the determination o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0706.1731v1-abstract-full').style.display = 'inline'; document.getElementById('0706.1731v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0706.1731v1-abstract-full" style="display: none;"> We present an analysis of high resolution VLT-FLAMES spectra of 61 B-type stars with relatively narrow-lined spectra located in 4 fields centered on the Milky Way clusters; NGC3293 & NGC4755 and the Large and Small Magellanic cloud clusters; NGC2004 and NGC330. For each object a quantitative analysis was carried out using the non-LTE model atmosphere code TLUSTY; resulting in the determination of their atmospheric parameters and photospheric abundances of the dominant metal species (C, N, O, Mg, Si, Fe). The results are discussed in relation to our earlier work on 3 younger clusters in these galaxies; NGC6611, N11 and NGC346 paying particular attention to the nitrogen abundances which are an important probe of the role of rotation in the evolution of stars. This work along with that of the younger clusters provides a consistent dataset of abundances and atmospheric parameters for over 100 B-type stars in the three galaxies. We provide effective temperature scales for B-type dwarfs in all three galaxies and for giants and supergiants in the SMC and LMC. In each galaxy a dependence on luminosity is found between the three classes with the unevolved dwarf objects having significantly higher effective temperatures. A metallicity dependence is present between the SMC and Galactic dwarf objects, and whilst the LMC stars are only slightly cooler than the SMC stars, they are significantly hotter than their Galactic counterparts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0706.1731v1-abstract-full').style.display = 'none'; document.getElementById('0706.1731v1-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 June, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">Paper accepted by A&A on 6/6/2007. 20 pages, 6 figures, 10 tables, plus online data. Part of a series of papers on The VLT-FLAMES survey of massive star</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/0609710">arXiv:astro-ph/0609710</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0609710">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0609710">ps</a>, <a href="https://arxiv.org/format/astro-ph/0609710">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/10.1051/0004-6361:20066148">10.1051/0004-6361:20066148 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES survey of massive stars: Surface chemical compositions of B-type stars in the Magellanic Clouds </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Hubeny%2C+I">I. Hubeny</a>, <a href="/search/?searchtype=author&query=Lanz%2C+T">T. Lanz</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/0609710v2-abstract-short" style="display: inline;"> We present an analysis of high-resolution FLAMES spectra of approximately 50 early B-type stars in three young clusters at different metallicities, NGC6611 in the Galaxy, N11 in the Large Magellanic Cloud (LMC) and NGC346 in the Small Magellanic Cloud (SMC). Using the TLUSTY non-LTE model atmospheres code, atmospheric parameters and photospheric abundances (C, N, O, Mg and Si) of each star have… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0609710v2-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0609710v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0609710v2-abstract-full" style="display: none;"> We present an analysis of high-resolution FLAMES spectra of approximately 50 early B-type stars in three young clusters at different metallicities, NGC6611 in the Galaxy, N11 in the Large Magellanic Cloud (LMC) and NGC346 in the Small Magellanic Cloud (SMC). Using the TLUSTY non-LTE model atmospheres code, atmospheric parameters and photospheric abundances (C, N, O, Mg and Si) of each star have been determined. These results represent a significant improvement on the number of Magellanic Cloud B-type stars with detailed and homogeneous estimates of their atmospheric parameters and chemical compositions. The relationships between effective temperature and spectral type are discussed for all three metallicity regimes, with the effective temperature for a given spectral type increasing as one moves to a lower metallicity regime. Additionally the difficulties in estimating the microturbulent velocity and the anomalous values obtained, particularly in the lowest metallicity regime, are discussed. Our chemical composition estimates are compared with previous studies, both stellar and interstellar with, in general, encouraging agreement being found. Abundances in the Magellanic Clouds relative to the Galaxy are discussed and we also present our best estimates of the base-line chemical composition of the LMC and SMC as derived from B-type stars. Additionally we discuss the use of nitrogen as a probe of the evolutionary history of stars, investigating the roles of rotational mixing, mass-loss, blue loops and binarity on the observed nitrogen abundances and making comparisons with stellar evolutionary models where possible. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0609710v2-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0609710v2-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 November, 2006; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 September, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2006. </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">A&A accepted. 32 pages, 14 figures reduced in quality. Replaced version updated with correct masses for LMC objects. Full quality version and online data available at http://star.pst.qub.ac.uk/~ih/</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astron.Astrophys.466:277-300,2007 </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/0606409">arXiv:astro-ph/0606409</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0606409">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0606409">ps</a>, <a href="https://arxiv.org/format/astro-ph/0606409">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/10.1051/0004-6361:20065392">10.1051/0004-6361:20065392 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES Survey of Massive Stars: Stellar parameters and rotational velocities in NGC3293, NGC4755 and NGC6611 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Lee%2C+J+K">J. K. Lee</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Hunter%2C+I">I. Hunter</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Irwin%2C+M+J">M. J. Irwin</a>, <a href="/search/?searchtype=author&query=Kaufer%2C+A">A. Kaufer</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/0606409v1-abstract-short" style="display: inline;"> An analysis is presented of VLT-FLAMES spectroscopy for three Galactic clusters, NGC3293, NGC4755 and NGC6611. Non-LTE model atmosphere calculations have been used to estimate effective temperatures (from either the helium spectrum or the silicon ionization equilibrium) and gravities (from the hydrogen spectrum). Projected rotational velocities have been deduced from the helium spectrum (for fas… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0606409v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0606409v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0606409v1-abstract-full" style="display: none;"> An analysis is presented of VLT-FLAMES spectroscopy for three Galactic clusters, NGC3293, NGC4755 and NGC6611. Non-LTE model atmosphere calculations have been used to estimate effective temperatures (from either the helium spectrum or the silicon ionization equilibrium) and gravities (from the hydrogen spectrum). Projected rotational velocities have been deduced from the helium spectrum (for fast and moderate rotators) or the metal line spectrum (for slow rotators). The observed Hertzsprung-Russell diagrams are compared with theoretical predictions and some discrepancies including differences in the main sequence luminosities are discussed. Cluster ages have been deduced and evidence for non-coeval star formation is found for all three of the clusters. Projected rotational velocities for targets in the older clusters, NGC3293 and NGC4755, have been found to be systematically larger than those for the field, confirming recent results in other similar age clusters. The distribution of projected rotational velocities are consistent with a Gaussian distribution of intrinsic rotational velocities. For the relatively unevolved targets in the older clusters, NGC3293 and NGC4755, the peak of the velocity distribution would be 250km/s with a full-width-half-maximum of approximately 180km/s. For NGC6611, the sample size is relatively small but implies a lower mean rotational velocity. This may be evidence for the spin-down effect due to angular momentum loss through stellar winds, although our results are consistent with those found for very young high mass stars. For all three clusters we deduce present day mass functions with Gamma-values in the range of -1.5 to -1.8, which are similar to other young stellar clusters in the Milky Way (Abridged). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0606409v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0606409v1-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 June, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2006. </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 A&A, version revised after referee's review</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/0606405">arXiv:astro-ph/0606405</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0606405">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0606405">ps</a>, <a href="https://arxiv.org/format/astro-ph/0606405">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/10.1051/0004-6361:20064988">10.1051/0004-6361:20064988 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES Survey of Massive Stars: Observations centered on the Magellanic Cloud clusters NGC 330, NGC 346, NGC 2004, and the N11 region </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</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/0606405v2-abstract-short" style="display: inline;"> We present new observations of 470 stars using the Fibre Large Array Multi-Element Spectrograph (FLAMES) instrument in fields centered on the clusters NGC 330 and NGC 346 in the Small Magellanic Cloud (SMC), and NGC 2004 and the N11 region in the Large Magellanic Cloud (LMC). A further 14 stars were observed in the N11 and NGC 330 fields using the Ultraviolet and Visual Echelle Spectrograph (UVE… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0606405v2-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0606405v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0606405v2-abstract-full" style="display: none;"> We present new observations of 470 stars using the Fibre Large Array Multi-Element Spectrograph (FLAMES) instrument in fields centered on the clusters NGC 330 and NGC 346 in the Small Magellanic Cloud (SMC), and NGC 2004 and the N11 region in the Large Magellanic Cloud (LMC). A further 14 stars were observed in the N11 and NGC 330 fields using the Ultraviolet and Visual Echelle Spectrograph (UVES) for a separate programme. Spectral classifications and stellar radial velocities are given for each target, with careful attention to checks for binarity. In particular we have investigated previously unexplored regions around the central LH9/LH10 complex of N11, finding ~25 new O-type stars from our spectroscopy. We have observed a relatively large number of Be-type stars that display permitted Fe II emission lines. These are primarily not in the cluster cores and appear to be associated with classical Be-type stars, rather than pre main-sequence objects. The presence of the Fe II emission, as compared to the equivalent width of H$伪$, is not obviously dependent on metallicity. We have also explored the relative fraction of Be- to normal B-type stars in the field-regions near to NGC 330 and NGC 2004, finding no strong evidence of a trend with metallicity when compared to Galactic results. A consequence of service observations is that we have reasonable time-sampling in three of our FLAMES fields. We find lower limits to the binary fraction of O- and early B-type stars of 23 to 36%. One of our targets (NGC346-013) is especially interesting with a massive, apparently hotter, less luminous secondary component. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0606405v2-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0606405v2-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 January, 2007; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 June, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2006. </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">35 pages, 17 figures (some reduced in size). Replacement copy, includes an erratum on the final page. A copy with full res. & embedded figures is at http://www.roe.ac.uk/~cje/flamesMC.ps.gz</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/0511840">arXiv:astro-ph/0511840</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0511840">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0511840">ps</a>, <a href="https://arxiv.org/format/astro-ph/0511840">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"> Massive Stars in the SMC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</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/0511840v1-abstract-short" style="display: inline;"> In this paper we review the observational data for OB stars in the SMC concentrating on those aspects of their spectra which provide information on processes which may strongly influence their evolution, namely mass-loss, rotational mixing and mass-transfer. We illustrate the very weak winds now thought to pertain to late O-dwarfs in the SMC, using HST/STIS observations of the main sequence in t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0511840v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0511840v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0511840v1-abstract-full" style="display: none;"> In this paper we review the observational data for OB stars in the SMC concentrating on those aspects of their spectra which provide information on processes which may strongly influence their evolution, namely mass-loss, rotational mixing and mass-transfer. We illustrate the very weak winds now thought to pertain to late O-dwarfs in the SMC, using HST/STIS observations of the main sequence in the very young cluster NGC346, briefly discussing the quantitative results for these stars, and the difficulties involved in their determination. We show how stars with similar luminosities can have different luminosity classes while stars with similar spectral types and luminosity classes can have significantly different luminosities. While the weak winds of the dwarfs present serious difficulties for the determination of wind terminal velocities we show that the supergiants have terminal velocities comparable to OB supergiants in the Milky Way, agreement with theory. We also summarize recent work demonstrating that the temperature dependence of wind terminal velocities does not follow the widely adopted step-like approximation. Finally we review surface compositons of OB stars in the SMC finding that 42 out of 45 OB stars with detailed surface abundances are enriched in nitrogen by a factor \~10 or more. While these enhancements are consistent with those produced by models with rotational mixing the rotational velocities of the sample are significantly lower than the values predicted by the modesls, indicating a possible problem with the evolution of angular momentum in the models or possibly in the efficiency of mixing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0511840v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0511840v1-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 November, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2005. </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, 5 figures, invited review to appear in "Stellar Evolution at Low Metallicity: Mass Loss, Explosions, Cosmology", (eds. Lamers, Langer & Nugis), fiddle Fig.4</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/0511758">arXiv:astro-ph/0511758</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0511758">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0511758">ps</a>, <a href="https://arxiv.org/format/astro-ph/0511758">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/10.1051/0004-6361:20054600">10.1051/0004-6361:20054600 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> B-type supergiants in the SMC: Rotational velocities and implications for evolutionary models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Simon-Diaz%2C+S">S. Simon-Diaz</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</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/0511758v2-abstract-short" style="display: inline;"> High-resolution spectra for 24 SMC and Galactic B-type supergiants have been analysed to estimate the contributions of both macroturbulence and rotation to the broadening of their metal lines. Two different methodologies are considered, viz. goodness-of-fit comparisons between observed and theoretical line profiles and identifying zeros in the Fourier transforms of the observed profiles. The adv… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0511758v2-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0511758v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0511758v2-abstract-full" style="display: none;"> High-resolution spectra for 24 SMC and Galactic B-type supergiants have been analysed to estimate the contributions of both macroturbulence and rotation to the broadening of their metal lines. Two different methodologies are considered, viz. goodness-of-fit comparisons between observed and theoretical line profiles and identifying zeros in the Fourier transforms of the observed profiles. The advantages and limitations of the two methods are briefly discussed with the latter techniques being adopted for estimated projected rotational velocities (\vsini) but the former being used to estimate macroturbulent velocities. Only one SMC supergiant, SK 191, shows a significant degree of rotational broadening (\vsini $\simeq$ 90 \kms). For the remaining targets, the distribution of projected rotational velocities are similar in both our Galactic and SMC samples with larger values being found at earlier spectral types. There is marginal evidence for the projected rotational velocities in the SMC being higher than those in the Galactic targets but any differences are only of the order of 5-10 \kms, whilst evolutionary models predict differences in this effective temperature range of typically 20 to 70 \kms. The combined sample is consistent with a linear variation of projected rotational velocity with effective temperature, which would imply rotational velocities for supergiants of 70 \kms at an effective temperature of 28 000 K (approximately B0 spectral type) decreasing to 32 \kms at 12 000 K (B8 spectral type). For all targets, the macroturbulent broadening would appear to be consistent with a Gaussian distribution (although other distributions cannot be discounted) with an $\frac{1}{e}$ half-width varying from approximately 20 \kms at B8 to 60 \kms at B0 spectral types. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0511758v2-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0511758v2-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 February, 2006; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 November, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2005. </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 figures, 8 pages, submitted to Astronomy and Astrophysics</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/0503655">arXiv:astro-ph/0503655</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0503655">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0503655">ps</a>, <a href="https://arxiv.org/format/astro-ph/0503655">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/10.1051/0004-6361:20042446">10.1051/0004-6361:20042446 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES Survey of Massive Stars: Observations in the Galactic Clusters NGC 3293, NGC 4755 and NGC 6611 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Lee%2C+J+-">J. -K. Lee</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Kaufer%2C+A">A. Kaufer</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/?searchtype=author&query=Simon-Diaz%2C+S">S. Simon-Diaz</a>, <a href="/search/?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/?searchtype=author&query=Hamann%2C+W+-">W. -R. Hamann</a>, <a href="/search/?searchtype=author&query=Hendry%2C+M+A">M. A. Hendry</a>, <a href="/search/?searchtype=author&query=Hunter%2C+I+K">I. K. Hunter</a>, <a href="/search/?searchtype=author&query=Irwin%2C+M+J">M. J. Irwin</a>, <a href="/search/?searchtype=author&query=Korn%2C+A+J">A. J. Korn</a>, <a href="/search/?searchtype=author&query=Kudritzki%2C+R+-">R. -P. Kudritzki</a>, <a href="/search/?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/?searchtype=author&query=Mokiem%2C+M+R">M. R. Mokiem</a>, <a href="/search/?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/?searchtype=author&query=Pauldrach%2C+A+W+A">A. W. A. Pauldrach</a>, <a href="/search/?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Urbaneja%2C+M+A">M. A. Urbaneja</a>, <a href="/search/?searchtype=author&query=Venn%2C+K+A">K. A. Venn</a> , et al. (1 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="astro-ph/0503655v2-abstract-short" style="display: inline;"> We introduce a new survey of massive stars in the Galaxy and the Magellanic Clouds using the Fibre Large Array Multi-Element Spectrograph (FLAMES) instrument at the Very Large Telescope (VLT). Here we present observations of 269 Galactic stars with the FLAMES-Giraffe Spectrograph (R ~ 25,000), in fields centered on the open clusters NGC 3293, NGC 4755 and NGC 6611. These data are supplemented by… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0503655v2-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0503655v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0503655v2-abstract-full" style="display: none;"> We introduce a new survey of massive stars in the Galaxy and the Magellanic Clouds using the Fibre Large Array Multi-Element Spectrograph (FLAMES) instrument at the Very Large Telescope (VLT). Here we present observations of 269 Galactic stars with the FLAMES-Giraffe Spectrograph (R ~ 25,000), in fields centered on the open clusters NGC 3293, NGC 4755 and NGC 6611. These data are supplemented by a further 50 targets observed with the Fibre-Fed Extended Range Optical Spectrograph (FEROS, R = 48,000). Following a description of our scientific motivations and target selection criteria, the data reduction methods are described; of critical importance the FLAMES reduction pipeline is found to yield spectra that are in excellent agreement with less automated methods. Spectral classifications and radial velocity measurements are presented for each star, with particular attention paid to morphological peculiarities and evidence of binarity. These observations represent a significant increase in the known spectral content of NGC 3293 and NGC 4755, and will serve as standards against which our subsequent FLAMES observations in the Magellanic Clouds will be compared. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0503655v2-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0503655v2-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 April, 2005; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 March, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2005. </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, 9 figures (reduced size). Accepted for publication in A&A. A copy with full res. figures is available from http://www.ing.iac.es/~cje/flames_mw.ps.gz. Minor changes following correction of proofs</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/0501228">arXiv:astro-ph/0501228</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0501228">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0501228">ps</a>, <a href="https://arxiv.org/format/astro-ph/0501228">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/10.1051/0004-6361:20042061">10.1051/0004-6361:20042061 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Understanding B-type supergiants in the low metallicity environment of the SMC II </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</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/0501228v1-abstract-short" style="display: inline;"> Despite a resurgence of effort over the last decade in the area of massive stars there is still ambiguity over their evolutionary path, contamination of their surface abundances and the behaviour of their stellar winds. Here 10 SMC B-type supergiants are analysed applying a unified model atmosphere code FASTWIND to intermediate resolution spectra from the ESO Multi Mode Instrument (EMMI) on the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0501228v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0501228v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0501228v1-abstract-full" style="display: none;"> Despite a resurgence of effort over the last decade in the area of massive stars there is still ambiguity over their evolutionary path, contamination of their surface abundances and the behaviour of their stellar winds. Here 10 SMC B-type supergiants are analysed applying a unified model atmosphere code FASTWIND to intermediate resolution spectra from the ESO Multi Mode Instrument (EMMI) on the NTT telescope. Combined with the 8 targets analysed in paper 1, this work provides observational results on the properties of the winds and chemical compositions of B-type supergiants in the SMC. This paper emphasizes and substantiates the implications for stellar evolution from paper 1; that current theoretical models need to produce larger degrees of surface nitrogen enhancements at lower rotational velocities. In addition a significant discrepancy between theoretical and observed mass-loss rates is discussed which will have important implications for the rotational velocities obtained from stellar evolution calculations. Furthermore, an initial calibration of the wind-momentum luminosity relationship for B-type supergiants in a low metallicity environment (Z = 0.004) is presented. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0501228v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0501228v1-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, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2005. </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 by A&A 5th Jan 2005, 14 pages, 9 postscript 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/astro-ph/0412367">arXiv:astro-ph/0412367</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0412367">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0412367">ps</a>, <a href="https://arxiv.org/format/astro-ph/0412367">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/10.1051/0004-6361:20042530">10.1051/0004-6361:20042530 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> B-type Supergiants in the SMC: Chemical compositions and comparison of static and unified models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Ryans%2C+R+S+I">R. S. I. Ryans</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Hubeny%2C+I">I. Hubeny</a>, <a href="/search/?searchtype=author&query=Lanz%2C+T">T. Lanz</a>, <a href="/search/?searchtype=author&query=Prieto%2C+C+A">C. Allende Prieto</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/0412367v1-abstract-short" style="display: inline;"> High-resolution UCLES/AAT spectra are presented for nine B-type supergiants in the SMC, chosen on the basis that they may show varying amounts of nuclear-synthetically processed material mixed to their surface. These spectra have been analysed using a new grid of approximately 12 000 non-LTE line blanketed {\sc tlusty} model atmospheres to estimate atmospheric parameters and chemical composition… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0412367v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0412367v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0412367v1-abstract-full" style="display: none;"> High-resolution UCLES/AAT spectra are presented for nine B-type supergiants in the SMC, chosen on the basis that they may show varying amounts of nuclear-synthetically processed material mixed to their surface. These spectra have been analysed using a new grid of approximately 12 000 non-LTE line blanketed {\sc tlusty} model atmospheres to estimate atmospheric parameters and chemical composition. The abundance estimates for O, Mg and Si are in excellent agreement with those deduced from other studies, whilst the low estimate for C may reflect the use of the \ion{C}{ii} doublet at 4267脜. The N estimates are approximately an order of magnitude greater than those found in unevolved B-type stars or \ion{H}{ii} regions but are consistent with the other estimates in AB-type supergiants. These results have been combined with results from a unified model atmosphere analysis of UVES/VLT spectra of B-type supergiants (Trundle et al. \cite{Tru04}) to discuss the evolutionary status of these objects. For two stars that are in common with those discussed by Trundle et al., we have undertaken a careful comparison in order to try to understand the relative importance of the different uncertainties present in such analyses, including observational errors and the use of static or unified models. We find that even for these relatively luminous supergiants, {\sc tlusty} models yield atmospheric parameters and chemical compositions similar to those deduced from the unified code {\sc fastwind}. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0412367v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0412367v1-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 December, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2004. </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 astronomy and astrophysics</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/0409398">arXiv:astro-ph/0409398</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0409398">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0409398">ps</a>, <a href="https://arxiv.org/format/astro-ph/0409398">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/10.1086/425563">10.1086/425563 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The ultraviolet and optical spectra of luminous B-type stars in the Small Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Walborn%2C+N+R">N. R. Walborn</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Rix%2C+S+A">S. A. Rix</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/0409398v1-abstract-short" style="display: inline;"> We present ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) of 12 early B-type stars in the Small Magellanic Cloud (SMC), comprising 9 supergiants and 3 giants. A morphological comparison with Galactic analogues is made using archival data from the International Ultraviolet Explorer (IUE). In general, the intensity of the P Cygni emission in the UV resonance lines is grea… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0409398v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0409398v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0409398v1-abstract-full" style="display: none;"> We present ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) of 12 early B-type stars in the Small Magellanic Cloud (SMC), comprising 9 supergiants and 3 giants. A morphological comparison with Galactic analogues is made using archival data from the International Ultraviolet Explorer (IUE). In general, the intensity of the P Cygni emission in the UV resonance lines is greater, and seen to later spectral types, in the Galactic spectra than in their metal-deficient SMC counterparts; we attribute these effects as most likely arising from weaker stellar winds in the SMC targets, as predicted by radiatively driven wind theory. We also include unpublished STIS observations of two late O-type stars in the SMC. In combination with the B-type observations, and published O-type data, we now have an extensive ultraviolet spectral library of metal-deficient stars, of use in the study of unresolved starbursts and high redshift, star-forming galaxies. In this context, we present empirical measurements for the B-type spectra of the new `1978 index' suggested by Rix et al. as a probe of metallicity in such systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0409398v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0409398v1-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 September, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2004. </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">24 pages, 7 figures (reduced size). Accepted for publication by PASP. A copy with full res. figures is available from http://www.ing.iac.es/~cje/bstars.ps.gz</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/0401399">arXiv:astro-ph/0401399</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0401399">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0401399">ps</a>, <a href="https://arxiv.org/format/astro-ph/0401399">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/10.1086/383306">10.1086/383306 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Terminal velocities of luminous, early-type SMC stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Heap%2C+S+R">S. R. Heap</a>, <a href="/search/?searchtype=author&query=Lindler%2C+D+J">D. J. Lindler</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/0401399v2-abstract-short" style="display: inline;"> Ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) are used to determine terminal velocities for 11 O and B-type giants and supergiants in the Small Magellanic Cloud (SMC) from the Si IV and C IV resonance lines. Using archival data from observations with the Goddard High-Resolution Spectrograph and the International Ultraviolet Explorer telescope, terminal velocities are o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0401399v2-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0401399v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0401399v2-abstract-full" style="display: none;"> Ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) are used to determine terminal velocities for 11 O and B-type giants and supergiants in the Small Magellanic Cloud (SMC) from the Si IV and C IV resonance lines. Using archival data from observations with the Goddard High-Resolution Spectrograph and the International Ultraviolet Explorer telescope, terminal velocities are obtained for a further five B-type supergiants. We discuss the metallicity dependence of stellar terminal velocities, finding no evidence for a significant scaling between Galactic and SMC metallicities for Teff < 30,000 K, consistent with the predictions of radiation driven wind theory for supergiant stars. A comparison of the $v_\infty / v_{esc}$ ratio between the SMC and Galactic samples, while consistent with the above statement, emphasizes that the uncertainties in the distances to galactic O-stars are a serious obstacle to a detailed comparison with theory. For the SMC sample there is considerable scatter in this ratio at a given effective temperature, perhaps indicative of uncertainties in stellar masses. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0401399v2-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0401399v2-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 March, 2004; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 January, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2004. </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">28 pages, 8 figures, accepted by ApJ; minor revisions prior to acceptance</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophys.J. 607 (2004) 451-459 </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/0312233">arXiv:astro-ph/0312233</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0312233">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0312233">ps</a>, <a href="https://arxiv.org/format/astro-ph/0312233">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/10.1051/0004-6361:20034325">10.1051/0004-6361:20034325 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Understanding B-type Supergiants in the Low Metallicity Environment of the SMC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</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/0312233v1-abstract-short" style="display: inline;"> Spectroscopic analyses of 7 SMC B-type supergiants and 1 giant have been undertaken using high resolution optical data obtained on the VLT with UVES. FASTWIND, a non-LTE, spherical,line-blanketed model atmosphere code was used to derive atmospheric and wind parameters of these stars as well as their absolute abundances. The implications of these results for stellar evolution and line driven wind… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0312233v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0312233v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0312233v1-abstract-full" style="display: none;"> Spectroscopic analyses of 7 SMC B-type supergiants and 1 giant have been undertaken using high resolution optical data obtained on the VLT with UVES. FASTWIND, a non-LTE, spherical,line-blanketed model atmosphere code was used to derive atmospheric and wind parameters of these stars as well as their absolute abundances. The implications of these results for stellar evolution and line driven wind theory are discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0312233v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0312233v1-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 December, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2003. </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">19 pages, 6 tables, 10 figures, accepted for publication in Astronomy and Astrophysics (5/12/2003)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astron.Astrophys. 417 (2004) 217-234 </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/0207198">arXiv:astro-ph/0207198</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0207198">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0207198">ps</a>, <a href="https://arxiv.org/format/astro-ph/0207198">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/10.1051/0004-6361:20021044">10.1051/0004-6361:20021044 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Chemical composition of B-type supergiants in the OB8, OB10, OB48, OB78 associations of M31 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</a>, <a href="/search/?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/?searchtype=author&query=Smartt%2C+S+J">S. J. Smartt</a>, <a href="/search/?searchtype=author&query=Urbaneja%2C+M+A">M. A. Urbaneja</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/0207198v1-abstract-short" style="display: inline;"> Absolute and differential chemical abundances are presented for the largest group of massive stars in M31 studied to date. These results were derived from intermediate resolution spectra of seven B-type supergiants, lying within four OB associations covering a galactocentric distance of 5 - 12 kpc. The results are mainly based on an LTE analysis, and we additionally present a full non-LTE, unifi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0207198v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0207198v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0207198v1-abstract-full" style="display: none;"> Absolute and differential chemical abundances are presented for the largest group of massive stars in M31 studied to date. These results were derived from intermediate resolution spectra of seven B-type supergiants, lying within four OB associations covering a galactocentric distance of 5 - 12 kpc. The results are mainly based on an LTE analysis, and we additionally present a full non-LTE, unified model atmosphere analysis of one star (OB78-277) to demonstrate the reliability of the differential LTE technique. A comparison of the stellar oxygen abundance with that of previous nebular results shows that there is an offset of between ~0.15 - 0.4 dex between the two methods which is critically dependent on the empirical calibration adopted for the R23 parameter with [O/H]. However within the typical errors of the stellar and nebular analyses (and given the strength of dependence of the nebular results on the calibration used) the oxygen abundances determined in each method are fairly consistent. We determine the radial oxygen abundance gradient from these stars, and do not detect any systematic gradient across this galactocentric range. We find that the inner regions of M31 are not, as previously thought, very 'metal rich'. Our abundances of C, N, O, Mg, Si, Al, S and Fe in the M31 supergiants are very similar to those of massive stars in the solar neighbourhood. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0207198v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0207198v1-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, 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">15 pages, 9 figures and 9 tables. Submitted to A&A April 2002</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astron.Astrophys. 395 (2002) 519-534 </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/0204464">arXiv:astro-ph/0204464</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0204464">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0204464">ps</a>, <a href="https://arxiv.org/format/astro-ph/0204464">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.1365-8711.2001.03999.x">10.1046/j.1365-8711.2001.03999.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optical spectroscopy of the M15 intermediate velocity cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Smoker%2C+J+V">J. V. Smoker</a>, <a href="/search/?searchtype=author&query=Keenan%2C+F+P">F. P. Keenan</a>, <a href="/search/?searchtype=author&query=Lehner%2C+N">N. Lehner</a>, <a href="/search/?searchtype=author&query=Trundle%2C+C">C. Trundle</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/0204464v1-abstract-short" style="display: inline;"> We present echelle spectrograph observations in NaD, at resolutions of 6.2-8.5 km/s, for 11 stars located in the line-of-sight to the M15 intermediate velocity cloud, which has a radial velocity of 70 km/s. This cloud is a part of IVC Complex gp. The targets range in magnitude from V=13.3-14.8. Seven of the observed stars are in the M15 globular cluster, the remaining four being field stars. Col… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0204464v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0204464v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0204464v1-abstract-full" style="display: none;"> We present echelle spectrograph observations in NaD, at resolutions of 6.2-8.5 km/s, for 11 stars located in the line-of-sight to the M15 intermediate velocity cloud, which has a radial velocity of 70 km/s. This cloud is a part of IVC Complex gp. The targets range in magnitude from V=13.3-14.8. Seven of the observed stars are in the M15 globular cluster, the remaining four being field stars. Column density ratios of log(N cm^-2)=11.8-12.5 are derived. Combining the current sightlines with previously-existing data, we find the NaD/HI ratio in the IVC varies by upto a factor of 25. One cluster star, M15 ZNG-1, was also observed in Calcium. We find N(CaI)/N(CaII)<0.03 and NaI/CaII=0.25, similar to values seen in the local ISM. Finally, we detect tentative evidence for IV absorption in KI towards 3 cluster stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0204464v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0204464v1-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 April, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">A&A, in press</span> </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. 322 (2001) 13 </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a 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