<?xml version="1.0" encoding="utf-8"?>
<TEI xmlns="http://www.tei-c.org/ns/1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:hal="http://hal.archives-ouvertes.fr/" xmlns:gml="http://www.opengis.net/gml/3.3/" xmlns:gmlce="http://www.opengis.net/gml/3.3/ce" version="1.1" xsi:schemaLocation="http://www.tei-c.org/ns/1.0 http://api.archives-ouvertes.fr/documents/aofr-sword.xsd">
  <teiHeader>
    <fileDesc>
      <titleStmt>
        <title>HAL TEI export of hal-04653688</title>
      </titleStmt>
      <publicationStmt>
        <distributor>CCSD</distributor>
        <availability status="restricted">
          <licence target="https://creativecommons.org/publicdomain/zero/1.0/">CC0 1.0 - Universal</licence>
        </availability>
        <date when="2026-05-02T03:00:07+02:00"/>
      </publicationStmt>
      <sourceDesc>
        <p part="N">HAL API Platform</p>
      </sourceDesc>
    </fileDesc>
  </teiHeader>
  <text>
    <body>
      <listBibl>
        <biblFull>
          <titleStmt>
            <title xml:lang="en">Observable and ionizing properties of star-forming galaxies with very massive stars and different IMFs</title>
            <author role="aut">
              <persName>
                <forename type="first">Daniel</forename>
                <surname>Schaerer</surname>
              </persName>
              <idno type="idhal" notation="numeric">756032</idno>
              <idno type="halauthorid" notation="string">124767-756032</idno>
              <idno type="ORCID">https://orcid.org/0000-0001-7144-7182</idno>
              <idno type="IDREF">https://www.idref.fr/057049912</idno>
              <affiliation ref="#struct-85978"/>
              <affiliation ref="#struct-1612967"/>
            </author>
            <author role="aut">
              <persName>
                <forename type="first">J</forename>
                <surname>Guibert</surname>
              </persName>
              <idno type="halauthorid">3199230-0</idno>
              <affiliation ref="#struct-85978"/>
            </author>
            <author role="aut">
              <persName>
                <forename type="first">Rui</forename>
                <surname>Marques-Chaves</surname>
              </persName>
              <idno type="idhal" notation="numeric">1443342</idno>
              <idno type="halauthorid" notation="string">1218408-1443342</idno>
              <idno type="ORCID">https://orcid.org/0000-0001-8442-1846</idno>
              <affiliation ref="#struct-85978"/>
            </author>
            <author role="aut">
              <persName>
                <forename type="first">Fabrice</forename>
                <surname>Martins</surname>
              </persName>
              <email type="md5">6a1c988502cd43757e123d2872b5dd91</email>
              <email type="domain">umontpellier.fr</email>
              <idno type="idhal" notation="string">fabrice-martins</idno>
              <idno type="idhal" notation="numeric">171832</idno>
              <idno type="halauthorid" notation="string">33893-171832</idno>
              <idno type="ORCID">https://orcid.org/0000-0001-5496-4567</idno>
              <idno type="IDREF">https://www.idref.fr/08409141X</idno>
              <affiliation ref="#struct-1100810"/>
            </author>
            <editor role="depositor">
              <persName>
                <forename>Nathalie</forename>
                <surname>POTHIER</surname>
              </persName>
              <email type="md5">bbadcf873be535d1d251be6425ad67be</email>
              <email type="domain">cnrs-orleans.fr</email>
            </editor>
          </titleStmt>
          <editionStmt>
            <edition n="v1" type="current">
              <date type="whenSubmitted">2025-08-09 07:54:21</date>
              <date type="whenModified">2025-10-22 18:04:09</date>
              <date type="whenReleased">2025-08-09 07:54:21</date>
              <date type="whenProduced">2025</date>
              <date type="whenEndEmbargoed">2025-08-09</date>
              <ref type="file" target="https://hal.science/hal-04653688v1/document">
                <date notBefore="2025-08-09"/>
              </ref>
              <ref type="file" subtype="greenPublisher" n="1" target="https://hal.science/hal-04653688v1/file/aa51454-24.pdf" id="file-5204767-4481665">
                <date notBefore="2025-08-09"/>
              </ref>
              <ref type="externalLink" target="http://arxiv.org/pdf/2407.12122"/>
            </edition>
            <respStmt>
              <resp>contributor</resp>
              <name key="106505">
                <persName>
                  <forename>Nathalie</forename>
                  <surname>POTHIER</surname>
                </persName>
                <email type="md5">bbadcf873be535d1d251be6425ad67be</email>
                <email type="domain">cnrs-orleans.fr</email>
              </name>
            </respStmt>
          </editionStmt>
          <publicationStmt>
            <distributor>CCSD</distributor>
            <idno type="halId">hal-04653688</idno>
            <idno type="halUri">https://hal.science/hal-04653688</idno>
            <idno type="halBibtex">schaerer:hal-04653688</idno>
            <idno type="halRefHtml">&lt;i&gt;Astronomy &amp; Astrophysics - A&amp;A&lt;/i&gt;, 2025, 693, pp.A271. &lt;a target="_blank" href="https://dx.doi.org/10.1051/0004-6361/202451454"&gt;&amp;#x27E8;10.1051/0004-6361/202451454&amp;#x27E9;&lt;/a&gt;</idno>
            <idno type="halRef">Astronomy &amp; Astrophysics - A&amp;A, 2025, 693, pp.A271. &amp;#x27E8;10.1051/0004-6361/202451454&amp;#x27E9;</idno>
            <availability status="restricted">
              <licence target="https://creativecommons.org/licenses/by/4.0/">CC BY 4.0 - Attribution<ref corresp="#file-5204767-4481665"/></licence>
            </availability>
          </publicationStmt>
          <seriesStmt>
            <idno type="stamp" n="IN2P3">Institut National de Physique Nucléaire et de Physique des Particules</idno>
            <idno type="stamp" n="INSU">INSU - Institut National des Sciences de l'Univers</idno>
            <idno type="stamp" n="UNIV-TLSE3">Université de Toulouse</idno>
            <idno type="stamp" n="CNRS">CNRS - Centre national de la recherche scientifique</idno>
            <idno type="stamp" n="OMP">Observatoire Midi-Pyrénées</idno>
            <idno type="stamp" n="OMP-IRAP" corresp="OMP">IRAP : Institut de recherche en astrophysique et planétologie</idno>
            <idno type="stamp" n="LUPM">Laboratoire Univers et Particules de Montpellier</idno>
            <idno type="stamp" n="UNIV-MONTPELLIER">Université de Montpellier</idno>
            <idno type="stamp" n="LUPM_AS" corresp="LUPM">Astrophysique Stellaire</idno>
            <idno type="stamp" n="UNIV-UT3">Université Toulouse 3</idno>
            <idno type="stamp" n="UT3-INP">Université de Toulouse / Toulouse INP</idno>
            <idno type="stamp" n="UT3-TOULOUSEINP">Université de Toulouse / Toulouse INP</idno>
            <idno type="stamp" n="UM-2015-2021" corresp="UNIV-MONTPELLIER">Université de Montpellier (2015-2021)</idno>
            <idno type="stamp" n="UM-EPE" corresp="UNIV-MONTPELLIER">Université de Montpellier - EPE</idno>
          </seriesStmt>
          <notesStmt>
            <note type="audience" n="2">International</note>
            <note type="popular" n="0">No</note>
            <note type="peer" n="1">Yes</note>
          </notesStmt>
          <sourceDesc>
            <biblStruct>
              <analytic>
                <title xml:lang="en">Observable and ionizing properties of star-forming galaxies with very massive stars and different IMFs</title>
                <author role="aut">
                  <persName>
                    <forename type="first">Daniel</forename>
                    <surname>Schaerer</surname>
                  </persName>
                  <idno type="idhal" notation="numeric">756032</idno>
                  <idno type="halauthorid" notation="string">124767-756032</idno>
                  <idno type="ORCID">https://orcid.org/0000-0001-7144-7182</idno>
                  <idno type="IDREF">https://www.idref.fr/057049912</idno>
                  <affiliation ref="#struct-85978"/>
                  <affiliation ref="#struct-1612967"/>
                </author>
                <author role="aut">
                  <persName>
                    <forename type="first">J</forename>
                    <surname>Guibert</surname>
                  </persName>
                  <idno type="halauthorid">3199230-0</idno>
                  <affiliation ref="#struct-85978"/>
                </author>
                <author role="aut">
                  <persName>
                    <forename type="first">Rui</forename>
                    <surname>Marques-Chaves</surname>
                  </persName>
                  <idno type="idhal" notation="numeric">1443342</idno>
                  <idno type="halauthorid" notation="string">1218408-1443342</idno>
                  <idno type="ORCID">https://orcid.org/0000-0001-8442-1846</idno>
                  <affiliation ref="#struct-85978"/>
                </author>
                <author role="aut">
                  <persName>
                    <forename type="first">Fabrice</forename>
                    <surname>Martins</surname>
                  </persName>
                  <email type="md5">6a1c988502cd43757e123d2872b5dd91</email>
                  <email type="domain">umontpellier.fr</email>
                  <idno type="idhal" notation="string">fabrice-martins</idno>
                  <idno type="idhal" notation="numeric">171832</idno>
                  <idno type="halauthorid" notation="string">33893-171832</idno>
                  <idno type="ORCID">https://orcid.org/0000-0001-5496-4567</idno>
                  <idno type="IDREF">https://www.idref.fr/08409141X</idno>
                  <affiliation ref="#struct-1100810"/>
                </author>
              </analytic>
              <monogr>
                <idno type="halJournalId" status="VALID">10858</idno>
                <idno type="issn">0004-6361</idno>
                <idno type="eissn">1432-0746</idno>
                <title level="j">Astronomy &amp; Astrophysics - A&amp;A</title>
                <imprint>
                  <publisher>EDP Sciences</publisher>
                  <biblScope unit="volume">693</biblScope>
                  <biblScope unit="pp">A271</biblScope>
                  <date type="datePub">2025</date>
                </imprint>
              </monogr>
              <idno type="arxiv">2407.12122</idno>
              <idno type="doi">10.1051/0004-6361/202451454</idno>
              <idno type="inspire">2808656</idno>
            </biblStruct>
          </sourceDesc>
          <profileDesc>
            <langUsage>
              <language ident="en">English</language>
            </langUsage>
            <textClass>
              <keywords scheme="author">
                <term xml:lang="en">ﬁrst stars</term>
                <term xml:lang="en">reionization</term>
                <term xml:lang="en">Dark ages</term>
                <term xml:lang="en">Galaxies: stellar content</term>
                <term xml:lang="en">Galaxies: ISM</term>
                <term xml:lang="en">Galaxies: high-redshift</term>
              </keywords>
              <classCode scheme="halDomain" n="phys.astr">Physics [physics]/Astrophysics [astro-ph]</classCode>
              <classCode scheme="halTypology" n="ART">Journal articles</classCode>
              <classCode scheme="halOldTypology" n="ART">Journal articles</classCode>
              <classCode scheme="halTreeTypology" n="ART">Journal articles</classCode>
            </textClass>
            <abstract xml:lang="en">
              <p>The presence of very massive stars (VMS, masses $&amp;gt;100$ M$_{\odot}$) is now firmly established in the local group, nearby galaxies, and out to cosmological distances. If present, these stars could boost the UV luminosity and ionizing photon production of galaxies, helping thus to alleviate the overabundance of UV-bright galaxies found with the JWST at high-redshift. Combing consistent stellar evolution and atmosphere models tailored to VMS we compute spectral energy distributions (SEDs) for a large set of models. We find that VMS contribute significantly to the UV luminosity and Lyman continuum of young stellar populations, and they are characterized by strong stellar HeII1640 emission, with EW(HeII) up to 4-8 Ang at young ages or $\sim 2.5-4$ Ang for constant SFR. For IMFs with a Salpeter slope, the boost of the UV luminosity is relatively modest. However, small changes in the IMF slope (e.g.~from $\alpha_2=-2.35$ to $-2$) lead to large increases in $L_{UV}$ and the ionizing photon production $Q$. Emission line strengths and the ionizing photon efficiency $\xi_{\rm ion}$ are also increased with VMS. Interestingly, SEDs including VMS show smaller Lyman breaks, and the shape of the ionizing spectra remain unaltered up to $\sim 35$ eV, but becomes softer at higher energies. We derive and discuss the maximum values quantities such as $L_{UV}$ per stellar mass or unit SFR, and $\xi_{\rm ion}$, $Q$ can reach when VMS are included, and we show that these values become essentially independent of the IMF. We propose observational methods to test for VMS and constrain the IMF. Finally, using JWST observations, we examine if high-redshift galaxies show some evidence of the presence of VMS and signs of non-standard IMFs. Very top-heavy IMFs can be excluded on average, but the IMF could well extend into the regime of VMS and be flatter than Salpeter in the bulk of high-$z$ galaxies. (abridged)</p>
            </abstract>
          </profileDesc>
        </biblFull>
      </listBibl>
    </body>
    <back>
      <listOrg type="structures">
        <org type="laboratory" xml:id="struct-85978" status="VALID">
          <orgName>Observatoire Astronomique de l'Université de Genève</orgName>
          <orgName type="acronym">ObsGE</orgName>
          <desc>
            <address>
              <addrLine>chemin des Maillettes CH-1290 Sauverny</addrLine>
              <country key="CH"/>
            </address>
            <ref type="url">http://www.unige.ch/sciences/astro/</ref>
          </desc>
          <listRelation>
            <relation active="#struct-154620" type="direct"/>
          </listRelation>
        </org>
        <org type="laboratory" xml:id="struct-1612967" status="VALID">
          <idno type="IdRef">232951217</idno>
          <idno type="ISNI">0000 0001 1994 662X</idno>
          <idno type="RNSR">201119477C</idno>
          <idno type="ROR">https://ror.org/05hm2ja81</idno>
          <orgName>Institut de recherche en astrophysique et planétologie</orgName>
          <orgName type="acronym">IRAP</orgName>
          <date type="start">2025-01-01</date>
          <desc>
            <address>
              <addrLine>9 avenue Colonel Roche 31028 Toulouse</addrLine>
              <country key="FR"/>
            </address>
            <ref type="url">http://www.irap.omp.eu/</ref>
          </desc>
          <listRelation>
            <relation name="UMR5277" active="#struct-300045" type="direct"/>
            <relation name="UMR5277" active="#struct-441569" type="direct"/>
            <relation active="#struct-1574795" type="direct"/>
            <relation active="#struct-443875" type="indirect"/>
          </listRelation>
        </org>
        <org type="laboratory" xml:id="struct-1100810" status="VALID">
          <idno type="IdRef">176043152</idno>
          <idno type="ISNI">000000040382470X</idno>
          <idno type="RNSR">201119459H</idno>
          <idno type="ROR">https://ror.org/00nrbzg90</idno>
          <orgName>Laboratoire Univers et Particules de Montpellier</orgName>
          <orgName type="acronym">LUPM</orgName>
          <date type="start">2022-01-01</date>
          <desc>
            <address>
              <addrLine>Place Eugène Bataillon - CC 72 34095 Montpellier Cédex 05</addrLine>
              <country key="FR"/>
            </address>
            <ref type="url">https://www.lupm.in2p3.fr/</ref>
          </desc>
          <listRelation>
            <relation active="#struct-300046" type="direct"/>
            <relation name="UMR5299" active="#struct-441569" type="direct"/>
            <relation active="#struct-1100589" type="direct"/>
          </listRelation>
        </org>
        <org type="institution" xml:id="struct-154620" status="VALID">
          <idno type="ROR">https://ror.org/01swzsf04</idno>
          <orgName>Université de Genève = University of Geneva</orgName>
          <orgName type="acronym">UNIGE</orgName>
          <date type="start">1559-01-01</date>
          <desc>
            <address>
              <addrLine>24 rue du Général-Dufour CH - 1211 Genève 4Suisse</addrLine>
              <country key="CH"/>
            </address>
            <ref type="url">http://www.unige.ch/</ref>
          </desc>
        </org>
        <org type="institution" xml:id="struct-300045" status="VALID">
          <idno type="IdRef">029349265</idno>
          <idno type="ISNI">0000 0001 2154 1736</idno>
          <idno type="ROR">https://ror.org/04kdfz702</idno>
          <idno type="Wikidata">Q3152437</idno>
          <orgName>Institut national des sciences de l'Univers</orgName>
          <orgName type="acronym">INSU - CNRS</orgName>
          <date type="start">2007-04-19</date>
          <desc>
            <address>
              <addrLine>INSU-CNRS3 rue Michel-Ange, 75794 Paris Cedex 16</addrLine>
              <country key="FR"/>
            </address>
            <ref type="url">https://www.insu.cnrs.fr</ref>
          </desc>
        </org>
        <org type="regroupinstitution" xml:id="struct-441569" status="VALID">
          <idno type="IdRef">02636817X</idno>
          <idno type="ISNI">0000000122597504</idno>
          <idno type="ROR">https://ror.org/02feahw73</idno>
          <orgName>Centre National de la Recherche Scientifique</orgName>
          <orgName type="acronym">CNRS</orgName>
          <date type="start">1939-10-19</date>
          <desc>
            <address>
              <country key="FR"/>
            </address>
            <ref type="url">https://www.cnrs.fr/</ref>
          </desc>
        </org>
        <org type="institution" xml:id="struct-1574795" status="VALID">
          <orgName>Université de Toulouse</orgName>
          <orgName type="acronym">EPE UT</orgName>
          <date type="start">2025-01-01</date>
          <desc>
            <address>
              <addrLine>118 toute de Narbonne, 31062 Toulouse cedex 9</addrLine>
              <country key="FR"/>
            </address>
            <ref type="url">https://www.univ-tlse3.fr/</ref>
          </desc>
          <listRelation>
            <relation active="#struct-443875" type="direct"/>
          </listRelation>
        </org>
        <org type="regroupinstitution" xml:id="struct-443875" status="VALID">
          <idno type="ROR">https://ror.org/017tgbk05</idno>
          <orgName>Communauté d'universités et établissements de Toulouse</orgName>
          <orgName type="acronym">Comue de Toulouse</orgName>
          <desc>
            <address>
              <addrLine>41 Allée Jules Guesde, 31000 Toulouse</addrLine>
              <country key="FR"/>
            </address>
            <ref type="url">https://www.univ-toulouse.fr/</ref>
          </desc>
        </org>
        <org type="institution" xml:id="struct-300046" status="VALID">
          <idno type="IdRef">028227875</idno>
          <idno type="ISNI">0000000106643574</idno>
          <idno type="ROR">https://ror.org/03fd77x13</idno>
          <orgName>Institut National de Physique Nucléaire et de Physique des Particules du CNRS</orgName>
          <orgName type="acronym">IN2P3</orgName>
          <desc>
            <address>
              <addrLine>CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE3 rue Michel-Ange75794 PARIS CEDEX 16 - France</addrLine>
              <country key="FR"/>
            </address>
            <ref type="url">https://in2p3.cnrs.fr</ref>
          </desc>
        </org>
        <org type="regroupinstitution" xml:id="struct-1100589" status="VALID">
          <idno type="ROR">https://ror.org/051escj72</idno>
          <orgName>Université de Montpellier</orgName>
          <orgName type="acronym">UM</orgName>
          <date type="start">2022-01-01</date>
          <desc>
            <address>
              <addrLine>163 rue Auguste Broussonnet - 34090 Montpellier</addrLine>
              <country key="FR"/>
            </address>
            <ref type="url">http://www.umontpellier.fr/</ref>
          </desc>
        </org>
      </listOrg>
    </back>
  </text>
</TEI>