On the massive stellar population of the super star cluster <ASTROBJ>Westerlund 1</ASTROBJ>

<!DOCTYPE html>     <html class="no-js" lang="en">  <head> <title>On the massive stellar population of the super star cluster <ASTROBJ>Westerlund 1</ASTROBJ> - NASA/ADS</title>  <link rel="apple-touch-icon" sizes="180x180" href="//styles/favicon/apple-touch-icon.png" /> <link rel="icon" type="image/png" sizes="32x32" href="//styles/favicon/favicon-32x32.png" /> <link rel="icon" type="image/png" sizes="16x16" href="//styles/favicon/favicon-16x16.png" /> <link rel="manifest" href="//styles/favicon/site.webmanifest" /> <link rel="mask-icon" href="//styles/favicon/safari-pinned-tab.svg" color="#5bbad5" /> <meta name="apple-mobile-web-app-title" content="NASA ADS" /> <meta name="application-name" content="NASA ADS" /> <meta name="msapplication-TileColor" content="#ffc40d" /> <meta name="theme-color" content="#ffffff" />  <link rel="stylesheet" href="/styles/css/styles.css"> <meta name="robots" content="noarchive"> <link rel="canonical" href="http://ui.adsabs.harvard.edu/abs/2005A&A...434..949C/abstract"/> <meta name="description" content="We present new spectroscopic and photometric observations of the young Galactic open cluster <ASTROBJ>Westerlund 1</ASTROBJ> (Wd 1) that reveal a unique population of massive evolved stars. We identify ~200 cluster members and present spectroscopic classifications for ~25% of these. We find that all stars so classified are unambiguously post-Main Sequence objects, consistent with an apparent lack of an identifiable Main Sequence in our photometric data to V∼ 20. We are able to identify rich populations of Wolf Rayet stars, OB supergiants and short lived transitional objects. Of these, the latter group consists of both hot (Luminous Blue Variable and extreme B supergiant) and cool (Yellow Hypergiant and Red Supergiant) objects - we find that half the known Galactic population of YHGs resides within Wd 1. We obtain a mean V-M<SUB>V</SUB> ~ 25 mag from the cluster Yellow Hypergiants, implying a Main Sequence turnoff at or below M<SUB>V</SUB> =-5 (O7 V or later). Based solely on the masses inferred for the 53 spectroscopically classified stars, we determine an absolute minimum mass of ~1.5 × 10^3~M<SUB>⊙</SUB> for Wd 1. However, considering the complete photometrically and spectroscopically selected cluster population and adopting a Kroupa IMF we infer a likely mass for Wd 1 of ~10^5~M<SUB>⊙</SUB>, noting that inevitable source confusion and incompleteness are likely to render this an underestimate. As such, Wd 1 is the most massive compact young cluster yet identified in the Local Group, with a mass exceeding that of Galactic Centre clusters such as the Arches and Quintuplet. Indeed, the luminosity, inferred mass and compact nature of Wd 1 are comparable with those of Super Star Clusters - previously identified only in external galaxies - and is consistent with expectations for a Globular Cluster progenitor.">  <meta property="og:type" content="article"> <meta property="og:title" content="On the massive stellar population of the super star cluster <ASTROBJ>Westerlund 1</ASTROBJ>"> <meta property="og:site_name" content="NASA/ADS"> <meta property="og:description" content="We present new spectroscopic and photometric observations of the young Galactic open cluster <ASTROBJ>Westerlund 1</ASTROBJ> (Wd 1) that reveal a unique population of massive evolved stars. We identify ~200 cluster members and present spectroscopic classifications for ~25% of these. We find that all stars so classified are unambiguously post-Main Sequence objects, consistent with an apparent lack of an identifiable Main Sequence in our photometric data to V∼ 20. We are able to identify rich populations of Wolf Rayet stars, OB supergiants and short lived transitional objects. Of these, the latter group consists of both hot (Luminous Blue Variable and extreme B supergiant) and cool (Yellow Hypergiant and Red Supergiant) objects - we find that half the known Galactic population of YHGs resides within Wd 1. We obtain a mean V-M<SUB>V</SUB> ~ 25 mag from the cluster Yellow Hypergiants, implying a Main Sequence turnoff at or below M<SUB>V</SUB> =-5 (O7 V or later). Based solely on the masses inferred for the 53 spectroscopically classified stars, we determine an absolute minimum mass of ~1.5 × 10^3~M<SUB>⊙</SUB> for Wd 1. However, considering the complete photometrically and spectroscopically selected cluster population and adopting a Kroupa IMF we infer a likely mass for Wd 1 of ~10^5~M<SUB>⊙</SUB>, noting that inevitable source confusion and incompleteness are likely to render this an underestimate. As such, Wd 1 is the most massive compact young cluster yet identified in the Local Group, with a mass exceeding that of Galactic Centre clusters such as the Arches and Quintuplet. Indeed, the luminosity, inferred mass and compact nature of Wd 1 are comparable with those of Super Star Clusters - previously identified only in external galaxies - and is consistent with expectations for a Globular Cluster progenitor."> <meta property="og:url" content="https://ui.adsabs.harvard.edu/abs/2005A&A...434..949C/abstract"> <meta property="og:image" content="https://ui.adsabs.harvard.edu/styles/img/transparent_logo.svg"> <meta property="article:published_time" content="05/2005"> <meta property="article:author" content="Clark, J. S."> <meta property="article:author" content="Negueruela, I."> <meta property="article:author" content="Crowther, P. A."> <meta property="article:author" content="Goodwin, S. P.">  <meta name="citation_journal_title" content="Astronomy and Astrophysics"> <meta name="citation_authors" content="Clark, J. S.;Negueruela, I.;Crowther, P. A.;Goodwin, S. P."> <meta name="citation_title" content="On the massive stellar population of the super star cluster <ASTROBJ>Westerlund 1</ASTROBJ>"> <meta name="citation_date" content="05/2005"> <meta name="citation_volume" content="434"> <meta name="citation_issue" content="3"> <meta name="citation_firstpage" content="949"> <meta name="citation_doi" content="10.1051/0004-6361:20042413"> <meta name="citation_issn" content="0004-6361"> <meta name="citation_language" content="en"> <meta name="citation_keywords" content="stars: evolution"> <meta name="citation_keywords" content="open clusters and associations: individual: Westerlund 1"> <meta name="citation_keywords" content="galaxies: starburst"> <meta name="citation_keywords" content="Astrophysics"> <meta name="citation_abstract_html_url" content="https://ui.adsabs.harvard.edu/abs/2005A&A...434..949C/abstract"> <meta name="citation_publication_date" content="05/2005"> <meta name="citation_pdf_url" content="https://ui.adsabs.harvard.edu/link_gateway/2005A&A...434..949C/PUB_PDF"> <meta name="citation_lastpage" content="969" /> <meta name="citation_arxiv_id" content="arXiv:astro-ph/0504342" /> <link title="schema(PRISM)" rel="schema.prism" href="http://prismstandard.org/namespaces/1.2/basic/" /> <meta name="prism.publicationDate" content="05/2005" /> <meta name="prism.publicationName" content="A&A" /> <meta name="prism.issn" content="0004-6361" /> <meta name="prism.volume" content="434" /> <meta name="prism.startingPage" content="949" /> <meta name="prism.endingPage" content="969" /> <link title="schema(DC)" rel="schema.dc" href="http://purl.org/dc/elements/1.1/" /> <meta name="dc.identifier" content="doi:10.1051/0004-6361:20042413" /> <meta name="dc.date" content="05/2005" /> <meta name="dc.source" content="A&A" /> <meta name="dc.title" content="On the massive stellar population of the super star cluster <ASTROBJ>Westerlund 1</ASTROBJ>" /> <meta name="dc.creator" content="Clark, J. S."> <meta name="dc.creator" content="Negueruela, I."> <meta name="dc.creator" content="Crowther, P. A."> <meta name="dc.creator" content="Goodwin, S. P.">  <meta name="twitter:card" content="summary_large_image"/> <meta name="twitter:description" content="We present new spectroscopic and photometric observations of the young Galactic open cluster <ASTROBJ>Westerlund 1</ASTROBJ> (Wd 1) that reveal a unique population of massive evolved stars. We identify ~200 cluster members and present spectroscopic classifications for ~25% of these. We find that all stars so classified are unambiguously post-Main Sequence objects, consistent with an apparent lack of an identifiable Main Sequence in our photometric data to V∼ 20. We are able to identify rich populations of Wolf Rayet stars, OB supergiants and short lived transitional objects. Of these, the latter group consists of both hot (Luminous Blue Variable and extreme B supergiant) and cool (Yellow Hypergiant and Red Supergiant) objects - we find that half the known Galactic population of YHGs resides within Wd 1. We obtain a mean V-M<SUB>V</SUB> ~ 25 mag from the cluster Yellow Hypergiants, implying a Main Sequence turnoff at or below M<SUB>V</SUB> =-5 (O7 V or later). Based solely on the masses inferred for the 53 spectroscopically classified stars, we determine an absolute minimum mass of ~1.5 × 10^3~M<SUB>⊙</SUB> for Wd 1. However, considering the complete photometrically and spectroscopically selected cluster population and adopting a Kroupa IMF we infer a likely mass for Wd 1 of ~10^5~M<SUB>⊙</SUB>, noting that inevitable source confusion and incompleteness are likely to render this an underestimate. As such, Wd 1 is the most massive compact young cluster yet identified in the Local Group, with a mass exceeding that of Galactic Centre clusters such as the Arches and Quintuplet. Indeed, the luminosity, inferred mass and compact nature of Wd 1 are comparable with those of Super Star Clusters - previously identified only in external galaxies - and is consistent with expectations for a Globular Cluster progenitor."/> <meta name="twitter:title" content="On the massive stellar population of the super star cluster <ASTROBJ>Westerlund 1</ASTROBJ>"/> <meta name="twitter:site" content="@adsabs"/> <meta name="twitter:domain" content="NASA/ADS"/> <meta name="twitter:image:src" content="https://ui.adsabs.harvard.edu/styles/img/transparent_logo.svg"/> <meta name="twitter:creator" content="@adsabs"/> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <base href="/"> <style> .btn-full-ads { color: #fff !important; background-color: #1a1a1a !important; border-color: #1a1a1a !important; margin-top: 9px !important; padding-bottom: 10px !important; padding-top: 10px !important; } .btn-full-ads:hover, .btn-full-ads:focus, .btn-full-ads:active, .btn-full-ads.active, .open>.dropdown-toggle.btn-full-ads { color: #000 !important; background-color: #ddd !important; border-color: #1a1a1a !important; } .dropdown-toggle:hover .dropdown-menu { display: block; } .navbar-nav.navbar-right:last-child { margin-right: -15px !important; } .navbar-right { @media screen (min-width: $screen-sm) { float: right!important; } } /*the container must be positioned relative:*/ .autocomplete { position: relative; display: inline-block; } .autocomplete-items { position: absolute; border: 1px solid #d4d4d4; border-bottom: none; border-top: none; z-index: 99; /*position the autocomplete items to be the same width as the container:*/ top: 100%; left: 0; right: 0; } .autocomplete-items div { padding: 10px; cursor: pointer; background-color: #fff; border-bottom: 1px solid #d4d4d4; } /*when hovering an item:*/ .autocomplete-items div:hover { background-color: #e9e9e9; } /*when navigating through the items using the arrow keys:*/ .autocomplete-active { background-color: #d7dfec !important; color: #000000; } </style> </head> <body> <div id="aria-announcement-container">Now on home page</div> <div id="app-container"> <div id="body-template-container"> <div class="s-master-page-manager"> <div id="navbar-container"> <div data-widget="NavbarWidget"> <nav class="navbar navbar-inverse"> <div class="container-fluid">  <div class=""> <ul class="nav navbar-nav navbar-left"> <li> <a class="navbar-brand" href="/"> <img class="s-ads-icon" src="/styles/img/transparent_logo.svg" alt="ads icon"/> <h1> <b>ads</b></h1> </a> </li> </ul> </div>  <div class="">  <ul class="nav navbar-nav navbar-right"> <li data-match-route="/"> <a href="/core/never/abs/2005A%26A...434..949C/abstract" style="transition: none; " class="btn btn-full-ads"> <i class="fa fa-refresh"></i> Enable full ADS </a> </li> </ul> </div> </div> </nav> </div> </div> <div id="content-container"> <div class="dynamic-container s-dynamic-container"> <div id="abstract-page-layout" class="s-abstract-page-layout"> <div class="row s-stable-search-bar-height s-results-control-row-container hidden-xs"> </div> <div class="row s-dynamic-page-body" id="dynamic-page-body"> <div class="s-abstract-content"> <div class="col-xs-12 col-sm-3 col-md-2" style="" id="left-column"> <div class="nav-container s-nav-container" style="transform: none; width: 100%; position: relative" id="left-column"> <nav> <div class="s-nav-header s-view-nav"> <i class="icon-list"></i> <h3>view </h3> </div> <a href="/abs/2005A%26A...434..949C/abstract" data-widget-id="ShowAbstract"> <div class="abstract-nav s-nav s-nav-selected"> <span class="s-content"> Abstract </span> </div> </a> </a> <a href="/abs/2005A%26A...434..949C/citations" aria-disabled="true" data-widget-id="ShowCitations"> <div class="abstract-nav s-nav "> <span class="s-content"> Citations <span class="num-items">(269)</span> </span> </div> </a> <a href="/abs/2005A%26A...434..949C/references" aria-disabled="true" data-widget-id="ShowReferences"> <div class="abstract-nav s-nav "> <span class="s-content"> References <span class="num-items">(85)</span> </span> </div> </a> <a href="/abs/2005A%26A...434..949C/coreads" aria-disabled="true" aria-disabled="true" data-widget-id="ShowCoreads"> <div class="abstract-nav s-nav "> <span class="s-content"> Co-Reads </span> </div> </a> <a href="/abs/2005A%26A...434..949C/similar" aria-disabled="true" data-widget-id="ShowSimilar"> <div class="abstract-nav s-nav "> <span class="s-content"> Similar Papers </span> </div> </a> <div aria-disabled="true" data-widget-id="ShowToc"> <div class="abstract-nav s-nav s-nav-inactive"> <span class="s-content"> Volume Content </span> </div> </div> <div href="#" data-widget-id="ShowGraphics"> <div class="abstract-nav s-nav s-nav-inactive"> <span class="s-content"> Graphics </span> </div> </div> <a href="/abs/2005A%26A...434..949C/metrics" data-widget-id="ShowMetrics"> <div class="abstract-nav s-nav"> <span class="s-content"> Metrics </span> </div> <a href="/abs/2005A%26A...434..949C/exportcitation" data-widget-id="ShowExportcitation__default"> <div class="abstract-nav s-nav "> <span class="content"> Export Citation </span> </div> </a> </nav> </div> </div> <div class="col-xs-12 col-sm-8 col-md-7 col-lg-7 s-middle-column" id="middle-column" style="padding-bottom: 0%">  <div class="main-content-container s-main-content-container" id="main-content" tabindex="-1" style="margin-bottom: 5px"> <div class="print-visible"> <h2 style="margin-left:6.1%;">NASA/ADS</h2> </div> <div id="abstract-title-container" class="s-abstract-title-container"> <div data-widget="ShowAbstract"> <article class="s-abstract-metadata">  <h2 class="s-abstract-title"> On the massive stellar population of the super star cluster <ASTROBJ>Westerlund 1</ASTROBJ> <a href=""></a> </h2> <div id="authors-and-aff" class="s-authors-and-aff"> <ul class="list-inline"> <li class="author"><a href="/search/?q=author%3A%22Clark%2C+J.+S.%22">Clark, J. S.</a> </li>; <li class="author"><a href="/search/?q=author%3A%22Negueruela%2C+I.%22">Negueruela, I.</a> </li>; <li class="author"><a href="/search/?q=author%3A%22Crowther%2C+P.+A.%22">Crowther, P. A.</a> </li>; <li class="author"><a href="/search/?q=author%3A%22Goodwin%2C+S.+P.%22">Goodwin, S. P.</a> </li> </ul> </div> <div class="s-abstract-text"> <h4 class="sr-only">Abstract</h4> <p> We present new spectroscopic and photometric observations of the young Galactic open cluster <ASTROBJ>Westerlund 1</ASTROBJ> (Wd 1) that reveal a unique population of massive evolved stars. We identify ~200 cluster members and present spectroscopic classifications for ~25% of these. We find that all stars so classified are unambiguously post-Main Sequence objects, consistent with an apparent lack of an identifiable Main Sequence in our photometric data to V∼ 20. We are able to identify rich populations of Wolf Rayet stars, OB supergiants and short lived transitional objects. Of these, the latter group consists of both hot (Luminous Blue Variable and extreme B supergiant) and cool (Yellow Hypergiant and Red Supergiant) objects - we find that half the known Galactic population of YHGs resides within Wd 1. We obtain a mean V-M<SUB>V</SUB> ~ 25 mag from the cluster Yellow Hypergiants, implying a Main Sequence turnoff at or below M<SUB>V</SUB> =-5 (O7 V or later). Based solely on the masses inferred for the 53 spectroscopically classified stars, we determine an absolute minimum mass of ~1.5 × 10^3~M<SUB>⊙</SUB> for Wd 1. However, considering the complete photometrically and spectroscopically selected cluster population and adopting a Kroupa IMF we infer a likely mass for Wd 1 of ~10^5~M<SUB>⊙</SUB>, noting that inevitable source confusion and incompleteness are likely to render this an underestimate. As such, Wd 1 is the most massive compact young cluster yet identified in the Local Group, with a mass exceeding that of Galactic Centre clusters such as the Arches and Quintuplet. Indeed, the luminosity, inferred mass and compact nature of Wd 1 are comparable with those of Super Star Clusters - previously identified only in external galaxies - and is consistent with expectations for a Globular Cluster progenitor. </p> </div> <br> <dl class="s-abstract-dl-horizontal"> <dt>Publication:</dt> <dd> <div id="article-publication">Astronomy and Astrophysics</div> </dd> <dt>Pub Date:</dt> <dd>May 2005</dd> <dt>DOI:</dt> <dd> <span> <a href="/link_gateway/2005A&A...434..949C/doi:10.1051/0004-6361:20042413" target="_blank" rel="noopener">10.1051/0004-6361:20042413</a> <i class="fa fa-external-link"></i> </span> </dd> <dt>arXiv:</dt> <dd> <span> <a href="/link_gateway/2005A&A...434..949C/arXiv:astro-ph/0504342" target="_blank" rel="noopener">arXiv:astro-ph/0504342</a> <i class="fa fa-external-link"></i> </span> </dd> <dt>Bibcode:</dt> <dd> <a href="/abs/2005A%26A...434..949C/abstract"> 2005A&A...434..949C </a> <i class="icon-help" title="The bibcode is assigned by the ADS as a unique identifier for the paper."></i> </dd> <dt>Keywords:</dt> <dd> <ul class="list-inline"> <li>stars: evolution;</li> <li>open clusters and associations: individual: Westerlund 1;</li> <li>galaxies: starburst;</li> <li>Astrophysics</li> </ul> </dd> <dt>E-Print:</dt> <dd> A&amp </dd> </dl> </article> </div> <div data-widget="ShowCitations"></div> <div data-widget="ShowReferences"></div> <div data-widget="ShowCoreads"></div> <div data-widget="ShowSimilar"></div> <div data-widget="ShowTableofcontents"></div> <div data-widget="ShowGraphics"></div> <div data-widget="ShowExportcitation" data-origin="abstract"></div> <div data-widget="ShowMetrics" data-allow-redirect="false"></div> <div data-widget="MetaTagsWidget"></div> </div> </div> </div> <div class="s-right-col-container col-xs-12 col-sm-12 col-md-3 col-lg-2 s-right-column" id="right-col-container" > <div data-widget="ShowResources"> <div data-reactroot="" class="s-right-col-widget-container" style="padding: 10px" > <div> <div class="resources__container"> <div class="resources__full__list"> <div class="resources__header__row"> <i class="fa fa-file-text-o" aria-hidden="true"> </i> <div class="resources__header__title">full text sources</div> </div> <div class="resources__content"> <div class="resources__content__title">Publisher</div> <div class="resources__content__links"> <span> <a href="/link_gateway/2005A&A...434..949C/PUB_PDF" rel="noopener" class="resources__content__link unlock" > <i class="fa fa-file-pdf-o" aria-hidden="true"> </i> </a> <div class="resources__content__link__separator">|</div> </span> <span> <a href="/link_gateway/2005A&A...434..949C/PUB_HTML" rel="noopener" class="resources__content__link unlock" > <i class="fa fa-file-text" aria-hidden="true"> </i> </a> </span> </div> </div> <div class="resources__content"> <div class="resources__content__title">arXiv</div> <div class="resources__content__links"> <span> <a href="/link_gateway/2005A&A...434..949C/EPRINT_PDF" rel="noopener" class="resources__content__link unlock" > <i class="fa fa-file-pdf-o" aria-hidden="true"> </i> </a> <div class="resources__content__link__separator">|</div> </span> <span> <a href="/link_gateway/2005A&A...434..949C/EPRINT_HTML" rel="noopener" class="resources__content__link unlock" > <i class="fa fa-file-text" aria-hidden="true"> </i> </a> </span> </div> </div> </div> <div class="resources__data__list"> <div class="resources__header__row"> <i class="fa fa-database"></i> <div class="resources__header__title">data products</div> </div> <div class="resources__content"> <a href="/link_gateway/2005A&A...434..949C/SIMBAD" rel="noopener" class="resources__content__link" >SIMBAD (109)</a > <a href="/link_gateway/2005A&A...434..949C/ESO" rel="noopener" class="resources__content__link" >ESO (2)</a > </div> </div> </div> <div data-widget="ShowAssociated"> </div> </div> </div> </div> <div data-widget="ShowGraphicsSidebar"> </div> </div> </div> </div> </div> </div> </div> <div id="footer-container"> <div data-widget="FooterWidget"> <div class="footer s-footer"> <footer> <div class="__footer_wrapper"> <div class="__footer_brand"> © The SAO/NASA Astrophysics Data System <div class="__footer_brand_extra"> <p> <i class="fa fa-envelope"></i> adshelp[at]cfa.harvard.edu </p> <p> The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement <em>NNX16AC86A</em> </p> </div> <div class="__footer_brand_logos"> <a href="http://www.nasa.gov" target="_blank" rel="noopener"> <img src="/styles/img/nasa.svg" alt="NASA logo" id="nasa-logo"> </a> <a href="http://www.si.edu" target="_blank" rel="noopener"> <img id="smithsonian-logo" src="/styles/img/smithsonian.svg" alt="Smithsonian logo"> </a> <a href="https://www.cfa.harvard.edu/" target="_blank" rel="noopener"> <img src="/styles/img/cfa.png" title="Harvard Center for Astrophysics logo" id="cfa-logo"> </a> </div> </div> <div class="__footer_list"> <div class="__footer_list_title"> Resources </div> <ul class="__footer_links"> <li> <a href="/about/" target="_blank" rel="noopener"> <i class="fa fa-question-circle"></i> About ADS </a> </li> <li> <a href="//ui.adsabs.harvard.edu/help/" target="_blank" rel="noopener"> <i class="fa fa-info-circle"></i> ADS Help </a> </li> <li> <a href="//ui.adsabs.harvard.edu/help/whats_new/" target="_blank" rel="noopener"> <i class="fa fa-bullhorn"></i> What's New </a> </li> <li> <a href="/about/careers/" target="_blank" rel="noopener"> <i class="fa fa-group"></i> Careers@ADS </a> </li> </ul> </div> <div class="__footer_list"> <div class="__footer_list_title"> Social </div> <ul class="__footer_links"> <li> <a href="//twitter.com/adsabs" target="_blank" rel="noopener"> <i class="fa fa-twitter"></i> @adsabs </a> </li> <li> <a href="//ui.adsabs.harvard.edu/blog/" target="_blank" rel="noopener"> <i class="fa fa-newspaper-o"></i> ADS Blog </a> </li> </ul> </div> <div class="__footer_list"> <div class="__footer_list_title"> Project </div> <ul class="__footer_links"> <li> <a href="/core/never">Switch to full ADS</a> </li> <li> <a href="https://adsisdownorjustme.herokuapp.com/" target="_blank" rel="noopener">Is ADS down? (or is it just me...)</a> </li> <li> <a href="http://www.si.edu" target="_blank" rel="noopener">Smithsonian Institution</a> </li> <li> <a href="http://www.si.edu/Privacy" target="_blank" rel="noopener">Smithsonian Privacy Notice</a> </li> <li> <a href="http://www.si.edu/Termsofuse" target="_blank" rel="noopener">Smithsonian Terms of Use</a> </li> <li> <a href="http://www.cfa.harvard.edu/sao" target="_blank" rel="noopener">Smithsonian Astrophysical Observatory</a> </li> <li> <a href="http://www.nasa.gov" target="_blank" rel="noopener">NASA</a> </li> </ul> </div> </div> </footer> </div> </div> </div> </div> </div> </div> <div id="darkSwitch" class="darkmode-toggle hidden" title="Turn on dark mode">🌓</div> <script> function autocomplete(searchBox, autoValues) { // Arguments: the text field element and an array of possible autocompleted values var currentFocus; // selected autocomplete option // Function to be run when the user types searchBox.addEventListener("input", function(e) { var a, b, i, val = this.value; // close any list of autocomplete values closeAllLists(); if (!val) { return false;} val = val.split(/\s+/); val = val[val.length - 1]; if (!val) { return false;} currentFocus = -1; // Create a DIV element that will contain the items (values): a = document.createElement("DIV"); a.setAttribute("id", this.id + "autocomplete-list"); a.setAttribute("class", "autocomplete-items"); // Append the DIV element as a child of the autocomplete container: this.parentNode.appendChild(a); for (i = 0; i < autoValues.length; i++) { // Check if the item starts with the same letters as the text field value: if (autoValues[i].match.substr(0, val.length).toUpperCase() == val.toUpperCase()) { // Create a DIV element for each matching element: b = document.createElement("DIV"); b.innerHTML = autoValues[i].label; if ("desc" in autoValues[i]) { b.innerHTML += " <i>" + autoValues[i].desc + "</i>"; } if (autoValues[i].value.startsWith(autoValues[i].match) ) { b.innerHTML += " | <strong>" + autoValues[i].match.substr(0, val.length) + "</strong>"; b.innerHTML += autoValues[i].match.substr(val.length); } // Insert a input field that will hold the current array item's value: b.innerHTML += "<input type='hidden' value='" + autoValues[i].value + "'>"; // Listen to clicks on the item value (DIV element): b.addEventListener("click", function(e) { var terms = searchBox.value.split(/\s+/); // Remove the current part of the input used for matching terms.pop(); // Insert the value for the autocomplete text field: terms.push(this.getElementsByTagName("input")[0].value); searchBox.value = terms.join(" "); // Move cursor position inside quotes/parenthesis if needed searchBox.focus(); if (searchBox.value[searchBox.value.length-1] === '"' || searchBox.value[searchBox.value.length-1] === ')') { searchBox.setSelectionRange(searchBox.value.length-1, searchBox.value.length-1); } // Close the list of autocompleted values closeAllLists(); }); a.appendChild(b); } } if (a.children.length > 0) { // By default, enter will select the first entry currentFocus = 0; addActive(a.children); } }); /*execute a function presses a key on the keyboard:*/ searchBox.addEventListener("keydown", function(e) { var x = document.getElementById(this.id + "autocomplete-list"); if (x) x = x.getElementsByTagName("div"); if (e.keyCode == 40) { // If the arrow DOWN key is pressed, increase the currentFocus variable: currentFocus++; addActive(x); } else if (e.keyCode == 38) { //up // If the arrow UP key is pressed, decrease the currentFocus variable: currentFocus--; /*and and make the current item more visible:*/ addActive(x); } else if (e.keyCode == 13) { // If the ENTER key is pressed: if (currentFocus > -1) { // Prevent the form from being submitted: e.preventDefault(); // Simulate a click on the "active" item: if (x) x[currentFocus].click(); currentFocus = -1; } } }); function addActive(x) { // Classify an item as "active": if (!x) return false; // Remove the "active" class on all items: removeActive(x); if (currentFocus >= x.length) currentFocus = 0; if (currentFocus < 0) currentFocus = (x.length - 1); // Add class "autocomplete-active": x[currentFocus].classList.add("autocomplete-active"); } function removeActive(x) { // Remove the "active" class from all autocomplete items: for (var i = 0; i < x.length; i++) { x[i].classList.remove("autocomplete-active"); } } function closeAllLists(elmnt) { // Close all autocomplete lists in the document, except the one passed as an argument: var x = document.getElementsByClassName("autocomplete-items"); for (var i = 0; i < x.length; i++) { if (elmnt != x[i] && elmnt != searchBox) { x[i].parentNode.removeChild(x[i]); } } } // Any other clicks in the document: document.addEventListener("click", function (e) { closeAllLists(e.target); }); } var autoList = [ { value: 'author:""', label: 'Author', match: 'author:"' }, { value: 'author:"^"', label: 'First Author', match: 'first author' }, { value: 'author:"^"', label: 'First Author', match: 'author:"^' }, { value: 'bibcode:""', label: 'Bibcode', desc: 'e.g. bibcode:1989ApJ...342L..71R', match: 'bibcode:"' }, { value: 'bibstem:""', label: 'Publication', desc: 'e.g. bibstem:ApJ', match: 'bibstem:"' }, { value: 'bibstem:""', label: 'Publication', desc: 'e.g. bibstem:ApJ', match: 'publication (bibstem)' }, { value: 'arXiv:', label: 'arXiv ID', match: 'arxiv:' }, { value: 'doi:', label: 'DOI', match: 'doi:' }, { value: 'full:""', label: 'Full text search', desc: 'title, abstract, and body', match: 'full:' }, { value: 'full:""', label: 'Full text search', desc: 'title, abstract, and body', match: 'fulltext' }, { value: 'full:""', label: 'Full text search', desc: 'title, abstract, and body', match: 'text' }, { value: 'year:', label: 'Year', match: 'year' }, { value: 'year:1999-2005', label: 'Year Range', desc: 'e.g. 1999-2005', match: 'year range' }, { value: 'aff:""', label: 'Affiliation', match: 'aff:' }, { value: 'abs:""', label: 'Search abstract + title + keywords', match: 'abs:' }, { value: 'database:astronomy', label: 'Limit to papers in the astronomy database', match: 'database:astronomy' }, { value: 'database:physics', label: 'Limit to papers in the physics database', match: 'database:physics' }, { value: 'title:""', label: 'Title', match: 'title:"' }, { value: 'orcid:', label: 'ORCiD identifier', match: 'orcid:' }, { value: 'object:', label: 'SIMBAD object (e.g. object:LMC)', match: 'object:' }, { value: 'property:refereed', label: 'Limit to refereed', desc: '(property:refereed)', match: 'refereed' }, { value: 'property:refereed', label: 'Limit to refereed', desc: '(property:refereed)', match: 'property:refereed' }, { value: 'property:notrefereed', label: 'Limit to non-refereed', desc: '(property:notrefereed)', match: 'property:notrefereed' }, { value: 'property:notrefereed', label: 'Limit to non-refereed', desc: '(property:notrefereed)', match: 'notrefereed' }, { value: 'property:eprint', label: 'Limit to eprints', desc: '(property:eprint)', match: 'eprint' }, { value: 'property:eprint', label: 'Limit to eprints', desc: '(property:eprint)', match: 'property:eprint' }, { value: 'property:openaccess', label: 'Limit to open access', desc: '(property:openaccess)', match: 'property:openaccess' }, { value: 'property:openaccess', label: 'Limit to open access', desc: '(property:openaccess)', match: 'openaccess' }, { value: 'doctype:software', label: 'Limit to software', desc: '(doctype:software)', match: 'software' }, { value: 'doctype:software', label: 'Limit to software', desc: '(doctype:software)', match: 'doctype:software' }, { value: 'property:inproceedings', label: 'Limit to papers in conference proceedings', desc: '(property:inproceedings)', match: 'proceedings' }, { value: 'property:inproceedings', label: 'Limit to papers in conference proceedings', desc: '(property:inproceedings)', match: 'property:inproceedings' }, { value: 'citations()', label: 'Citations', desc: 'Get papers citing your search result set', match: 'citations(' }, { value: 'references()', label: 'References', desc: 'Get papers referenced by your search result set', match: 'references(' }, { value: 'trending()', label: 'Trending', desc: 'Get papers most read by users who recently read your search result set', match: 'trending(' }, { value: 'reviews()', label: 'Review Articles', desc: 'Get most relevant papers that cite your search result set', match: 'reviews(' }, { value: 'useful()', label: 'Useful', desc: 'Get papers most frequently cited by your search result set', match: 'useful(' }, { value: 'similar()', label: 'Similar', desc: 'Get papers that have similar full text to your search result set', match: 'similar(' }, ]; // initiate the autocomplete function on the "q" element, and pass along the operators array as possible autocomplete values: inputBox = document.getElementById("q") if (inputBox) { inputBox.focus() // autofucs inputBox.setSelectionRange(inputBox.value.length, inputBox.value.length); // bring cursor to the end autocomplete(inputBox, autoList); } </script> <script> (function() { // turn off no-js if we have javascript document.documentElement.className = document.documentElement.className.replace("no-js", "js"); function getCookie(cname) { var name = cname + "="; var decodedCookie = decodeURIComponent(document.cookie); var ca = decodedCookie.split(';'); for (var i = 0; i < ca.length; i++) { var c = ca[i]; while (c.charAt(0) == ' ') { c = c.substring(1); } if (c.indexOf(name) == 0) { return c.substring(name.length, c.length); } } return ""; } (function() { // looks for the cookie, and sets true if its 'always' const coreCookie = getCookie('core') === 'always'; // only load bumblebee if we detect the core cookie and we are on abstract page if (coreCookie || (!(/^\/abs\//.test(document.location.pathname)) && !coreCookie)) { return; } window.__PRERENDERED = true; const addScript = function(args, cb) { const script = document.createElement('script'); Object.keys(args).forEach((key) => { script.setAttribute(key, args[key]); }); script.onload = function() { cb && cb(script); }; document.body.appendChild(script); } window.require = { waitSeconds: 0, baseUrl: '/' }; addScript({ src: '/libs/require.js' }, () => { addScript({ src: '/config/shim.js' }); }); })(); })(); </script> </body> </html>

CINXE.COM

On the massive stellar population of the super star cluster <ASTROBJ>Westerlund 1</ASTROBJ> - NASA/ADS