J/ApJ/948/35ivo://CDS.VizieR/J/ApJ/948/35doi:10.26093/cds/vizier.19480035CDSSaccardi A.Salvadori S.D'Odorico V.Cupani G.Fumagalli M.,Berg T.A.M.Becker G.D.Ellison S.Lopez S.2025-07-01T20:11:50Z2025-06-23T14:02:05ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frchemical-abundancesquasarsvisible-astronomyspectroscopyinfrared-astronomyultraviolet-astronomyredshiftedThe first stars were born from chemically pristine gas. They were likely massive, and thus they rapidly exploded as supernovae, enriching the surrounding gas with the first heavy elements. In the Local Group, the chemical signatures of the first stellar population were identified among low-mass, long-lived, very metal-poor ([Fe/H]{<}-2) stars, characterized by high abundances of carbon over iron ([C/Fe]>+0.7): the so-called carbon-enhanced metal-poor stars. Conversely, a similar carbon excess caused by first-star pollution was not found in dense neutral gas traced by absorption systems at different cosmic time. Here we present the detection of 14 very metal-poor, optically thick absorbers at redshift z~3-4. Among these, 3 are carbon-enhanced and reveal an overabundance with respect to Fe of all the analyzed chemical elements (O, Mg, Al, and Si). Their relative abundances show a distribution with respect to [Fe/H] that is in very good agreement with those observed in nearby very metal-poor stars. All the tests we performed support the idea that these C-rich absorbers preserve the chemical yields of the first stars. Our new findings suggest that the first-star signatures can survive in optically thick but relatively diffuse absorbers, which are not sufficiently dense to sustain star formation and hence are not dominated by the chemical products of normal stars.2023ApJ...948...35Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/948/35CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)J/AJ/130/2804 : Carbon abundances in metal-poor stars (Rossi+, 2005)J/A+A/501/519 : Extremely metal-poor turnoff stars abund. (Bonifacio+, 2009)J/ApJ/724/341 : Nucleosynthesis of massive metal-free stars (Heger+, 2010)J/ApJ/762/27 : Most metal-poor stars. III. [Fe/H]<=-3.0 stars (Yong+, 2013)J/ApJ/797/21 : Carbon-enhanced metal-poor stars (Placco+, 2014)J/A+A/581/A22 : 67 CEMP-s stars model analysis (Abate+, 2015)J/A+A/579/A28 : Abundances of 3 CEMP stars (Bonifacio+, 2015)J/MNRAS/462/3285 : XQ-100. X-shooter quasar spectra (Perrotta+, 2016)J/MNRAS/458/4074 : UVES Advanced Data Products QSO Sample. VI. (Quiret+, 2016)J/MNRAS/456/4488 : XQ-100 survey neutral gas (Sanchez-Ramirez+, 2016)J/ApJ/833/20 : Carbon-enhanced metal-poor (CEMP) star abund. (Yoon+, 2016)J/MNRAS/464/L56 : DLA properties and EW of 36 QSOs (Berg+, 2017)J/A+A/611/A76 : DLAS dust-corrected metallicity (De Cia+, 2018)J/ApJS/237/13 : Models and yields of massive stars (Limongi+, 2018)J/ApJ/857/111 : Stellar yields of rot. first stars. II. (Takahashi+, 2018)J/A+A/630/A104 : Disk and halo stars C, O and Fe abundances (Amarsi+, 2019)J/A+A/621/A108 : RVel compilation for 45 CEMP-no stars (Arentsen+ 2019)J/MNRAS/488/4356 : Sub-damped Ly{alpha} systems in XQ-100 survey (Berg+, 2019)J/MNRAS/482/3458 : UVES Spectral Quasar Absorption Database DR1 (Murphy+, 2019)J/ApJ/870/122 : Spectroscopy of low-metallicity star cand. (Placco+, 2019)J/MNRAS/502/4009 : Sub-damped Lyman {alpha} systems in XQ-100 II (Berg+, 2021)J/A+A/651/A79 : TO stars metallicity estimate (Bonifacio+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/948/35https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/948/35http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/948/35https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/948/35https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/948/35http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/948/35GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/948/35/table2 (Absorption redshift, neutral hydrogen column density, iron abundance, and relative chemical abundances for all absorption systems with a measure/Upper limit of FeII)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/948/35/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/948/35/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/948/35/table2?GETtext/xml+votable180.050000true10.5822678-10.33599250.0055555555555555566/514 4233 4267 4761 8277 16894 18200 18209 18466 26167 26233 26369 26492 26882 27436 27524 28173 30836 31313 31659 32466 33746 34262 35759 36466 36834https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/948/35?format=asciiUVOpticalInfrareddefaultJ/ApJ/948/35/table2Absorption redshift, neutral hydrogen column density, iron abundance, and relative chemical abundances for all absorption systems with a measure/Upper limit of FeIIrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameQSO name (JHHMM+DDMM) (G1)meta.id;meta.maincharprimaryf_NameFlag(s) on Name (1)meta.codecharzabs[3/4.3] Absorption redshiftsrc.redshiftdoubleNEDNED column added by the CDSmeta.ref.urlcharNHI[17.2/19.9] Neutral hydrogen column densityphys.columnDensity;em.line.HIfloate_NHI[0.15/0.3] NHI uncertaintystat.error;phys.columnDensity;em.line.HIfloatlogZ[-2.91/-0.25] Metal abundancelog(Sun)phys.abund.Zfloatl_[Fe/H]Limit flag on [Fe/H]meta.code.error;phys.abund.Fechar[Fe/H][-3.3/0.8] Fe/H abundancelog(Sun)phys.abund.Fefloate_[Fe/H][0.1/0.3]? [Fe/H] uncertaintylog(Sun)stat.error;phys.abund.Fefloatnullablel_[C/H]Limit flag on [C/H]meta.code.error;phys.abundchar[C/H][-2.55/2.1] C/H abundancelog(Sun)phys.abundfloate_[C/H][0.13/0.2]? [C/H] uncertaintylog(Sun)stat.error;phys.abundfloatnullablel_[O/H]Limit flag on [O/H]meta.code.error;phys.abundchar[O/H][-2.5/2.2]? O/H abundancelog(Sun)phys.abundfloatnullablee_[O/H][0.16/0.3]? [O/H] uncertaintylog(Sun)stat.error;phys.abundfloatnullablel_[Mg/H]Limit flag on [Mg/H]meta.code.error;phys.abundchar[Mg/H][-2.52/0.96]? Mg/H abundancelog(Sun)phys.abundfloatnullablee_[Mg/H][0.14/0.3]? [Mg/H] uncertaintylog(Sun)stat.error;phys.abundfloatnullable[Al/H][-3.2/-0.09]? Al/H abundancelog(Sun)phys.abundfloatnullablee_[Al/H][0.1/0.3]? [Al/H] uncertaintylog(Sun)stat.error;phys.abundfloatnullable[Si/H][-2.51/0.1] Si/H abundancelog(Sun)phys.abundfloate_[Si/H][0.12/0.3] [Si/H] uncertaintylog(Sun)stat.error;phys.abundfloatl_[C/Fe]Limit flag on [C/Fe]meta.code.error;phys.abundchar[C/Fe][-2.17/1.9] C/Fe abundance (2)log(Sun)phys.abundfloate_[C/Fe][0.07/0.3]? [C/Fe] uncertaintylog(Sun)stat.error;phys.abundfloatnullableXQ-100Display data from Perrotta+ 2016, J/MNRAS/462/3285 and Sanchez-Ramirez+ 2016, J/MNRAS/456/4488meta.ref.urlintnullableNtNumber of transition measurements for this QSO (link to Table 6)meta.numberintnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainSimbadNameSimbad column added by the CDSmeta.idcharnullableJ/ApJ/948/35/table6Voigt fit parametersNameSystem identifier (G1)meta.id;meta.maincharTransTransitionmeta.id;phys.atmol.transitionchare_logN[0/0.7]? Uncertainty in logNlog(cm**-2)stat.errorfloatnullableb[5/66]? Doppler broadening parameterspect.line.broadfloatnullablee_b[0/10]? Uncertainty in bstat.errorfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintzAvg[3/4.3] Average spectroscopic redshift of systemstat.mean;src.redshiftdoublez[3/4.5] Central spectroscopic redshift from Transsrc.redshiftdoublel_logNLimit flag on logNmeta.code.errorcharlogN[11.1/17.5] log column density in Translog(cm**-2)phys.columnDensityfloat