J/MNRAS/516/4164ivo://CDS.VizieR/J/MNRAS/516/4164doi:10.26093/cds/vizier.75164164CDSLorenzo M.Garcia M.Najarro F.Herrero A.Cervino M.Castro N.2024-09-02T20:16:02Z2023-07-31T08:17:21ZCDS support team

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

cds-question@unistra.frgalaxiesob-starsstellar-spectral-typesphotometryvisible-astronomyultraviolet-astronomyLocal Group (LG) very metal-poor massive stars are the best proxy for the First Stars of the Universe and fundamental to modelling the evolution of early galaxies. These stars may follow new evolutionary pathways restricted to very low metallicities, such as chemically homogeneous evolution (CHE). However, given the great distance leap needed to reach very metal-poor galaxies of the LG and vicinity, no comprehensive spectroscopic studies have been carried out at metallicities lower than the Small Magellanic Cloud (SMC; Z=1/5Z_{sun}_) until now. After five observing campaigns at the 10.4-m Gran Telescopio Canarias, we have assembled a low-resolution (R~1000) spectroscopic collection of more than 150 OB stars in the 1/10Z_{sun}_ galaxy Sextans A, increasing by an order of magnitude the number of massive stars known in this galaxy. The catalogue includes 38 BA-type supergiants, four red supergiants, and the first candidate 1/10Z_{sun}_ binary systems, CHE sources and systems hosting stripped stars. The sample massive stars mainly overlap the higher concentrations of neutral gas of Sextans A. However, we find some sources in low HI column-density regions. The colour-magnitude diagram of the galaxy presents large dispersion, which suggests uneven, internal extinction in Sextans A. This is the largest catalogue of OB-type stars ever produced at sub-SMC metallicities. This sample constitutes a fundamental first step to unveiling the evolutionary pathways and fates of very metal-poor massive stars, analyzing the dependence of radiation-driven winds with metallicity, and studying binary systems in an environment analogue to the early Universe.2022MNRAS.516.4164Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/516/4164CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/AJ/133/2393 : UBVRI phot. in seven Local Group dwarfs galaxies (Massey+ 2007)J/AJ/143/74 : HST photometry in 6 dwarf galaxies (Bianchi+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/516/4164https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/516/4164http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/516/4164https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/516/4164https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/516/4164http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/516/4164GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/516/4164/table123 (Blue type stars (from O to F types) confirmed by spectroscopy (1), spectral subtype not assigned (2) and late type stars (3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/516/4164/table123?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/516/4164/table123?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/516/4164/table123?GETtext/xml+votable180.050000true152.7720417-4.71158330.0055555555555555566/268589.922254260544722e-19 1.3189343879298211e-18https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/516/4164?format=asciiUVOpticaldefaultJ/MNRAS/516/4164/table123Blue type stars (from O to F types) confirmed by spectroscopy (1), spectral subtype not assigned (2) and late type stars (3)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTab1 for confirmed O to F types, 2 for O to F types spectral subtype not assigned, 3 for late type starsmeta.codecharoutliersindicates blue outliers in table 4meta.ref.urlcharIDIdentification code in this work (sNNN)meta.id;meta.maincharprimaryONameIdentification code in alternative photometric cataloguesphotcharn_OName[MBSH] Note on OName (1)meta.notecharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainSpTypeSpectral typesrc.spTypecharVmag? Visual magnitudemagphot.mag;em.opt.VfloatnullableB-V? Colour B-Vmagphot.color;em.opt.B;em.opt.VfloatnullableQ? Free reddening pseudo-colour Q (Q = (U-B)-0.72*(B-V)) (not in table3.dat)magphot.color.reddFreefloatnullableRVRadial velocity derived in this workkm/sphys.veloc;pos.heliocentricinte_RVUncertainty in the derived radial velocitykm/sstat.errorintn_RV[*] Note on RV (2)meta.notecharSNR? Signal-to-noise ratio per element of resolution calculated in a region free of spectral lines around 4800{AA} (not in table3.dat)stat.snrintnullableNotesAdditional information (3)meta.notecharJ/MNRAS/516/4164/table4List of blue outliers in the CMD of Sextans ArecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification code in this work (sNNN)meta.id;meta.maincharSpTypeSpectra typesrc.spTypecharVmagV magnitude from Massey et al. (2007AJ....133.2393M, Cat. J/AJ/133/2393)magphot.mag;em.opt.VfloatB-VB-V colour from Massey et al. (2007AJ....133.2393M, Cat. J/AJ/133/2393)magphot.color;em.opt.B;em.opt.VfloatUVdet[Yes No info] UV detection flagmeta.codecharF170W? F170W magnitude from Bianchi et al. (2012AJ....143...74B, Cat. J/AJ/143/74)magphot.mag;em.UV.100-200nmfloatnullableF170W-F225W? F170W-F225W colour frm Bianchi et al. (2012AJ....143...74B, Cat. J/AJ/143/74)magphot.color;em.UV.100-200nmfloatnullableUVout[Yes No -] flag the objects that are outliers in the UV CMDmeta.codecharlogLDerived luminosity (this work)log(solLum)phys.luminosityfloatlogLC? Calibrated luminosity for the corresponding spectral typelog(solLum)phys.luminosityfloatnullableBinary[Yes No] Whether or not the source presents signatures of multiplicity in its spectrameta.codecharBroad[Yes No ?] Whether or not the source line profiles are broader than models with vsini>300km/smeta.codecharTypeSuggested typesrc.classchar