J/MNRAS/450/3855ivo://CDS.VizieR/J/MNRAS/450/3855doi:10.26093/cds/vizier.74503855CDSMohr-Smith M.Drew J.E.Barentsen G.Wright N.J.Napiwotzki R.,Corradi R.L.M.Eisloffel J.Groot P.Kalari V.Parker Q.A.Raddi R.,Sale S.E.Unruh Y.C.Vink J.S.Wesson R.2024-08-14T20:22:00Z2017-10-27T13:43:04ZCDS support team

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

cds-question@unistra.fropen-star-clustersob-starsvisible-astronomysloan-photometryinfrared-photometryh-alpha-photometryO and early B stars are at the apex of galactic ecology, but in the Milky Way, only a minority of them may yet have been identified. We present the results of a pilot study to select and parametrize OB star candidates in the Southern Galactic plane, down to a limiting magnitude of g=20. A 2 deg^2^ field capturing the Carina Arm around the young massive star cluster, Westerlund 2, is examined. The confirmed OB stars in this cluster are used to validate our identification method, based on selection from the (u-g, g-r) diagram for the region. Our Markov Chain Monte Carlo fitting method combines VPHAS+ u, g, r, i with published J, H, K photometry in order to derive posterior probability distributions of the stellar parameters log(Teff) and distance modulus, together with the reddening parameters A_0_ and R_V_. The stellar parameters are sufficient to confirm OB status while the reddening parameters are determined to a precision of {sigma}(A_0_)~0.09 and {sigma}(R_V_)~0.08. There are 489 objects that fit well as new OB candidates, earlier than ~ B2. This total includes 74 probable massive O stars, 5 likely blue supergiants and 32 reddened subdwarfs. This increases the number of previously known and candidate OB stars in the region by nearly a factor of 10. Most of the new objects are likely to be at distances between 3 and 6 kpc. We have confirmed the results of previous studies that, at these longer distances, these sight lines require non-standard reddening laws with 3.5<R_V_<4.2015MNRAS.450.3855Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/450/3855CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/341 : VPHAS+ DR2 survey (Drew+, 2016)III/5 : Faint OB stars between Car and Cen (Lynga 1968)J/ApJS/87/197 : Carina OB2 association (Garcia+, 1993)J/A+A/477/593 : X-ray properties of Carina OB1 association (Antokhin+, 2008)J/ApJS/194/5 : Carina OB stars in the CCCP catalog (Gagne+, 2011)J/ApJS/194/6 : Candidate X-ray emitting OB stars in Carina (Povich+, 2011)J/ApJS/194/7 : X-ray properties of O and B stars in Carina (Naze+, 2011)J/ApJS/194/14 : A Pan-Carina YSO catalog (Povich+, 2011)J/A+A/549/A67 : Embedded YSOs in Carina Nebula complex (Gaczkowski+, 2013)J/A+A/572/A116 : The VISTA Carina Nebula Survey (Preibisch+, 2014)J/MNRAS/465/1807 : Deep OB star population in Carina (Mohr-Smith+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/450/3855https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/450/3855http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/450/3855https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/450/3855https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/450/3855http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/450/3855GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/450/3855/table56 (dat.Positions and photometry (table 5) and derived parameters (table 6)of all 1073 objects)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/450/3855/table56?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/450/3855/table56?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/450/3855/table56?GETtext/xml+votable180.050000true153.2885417-58.03280560.0055555555555555566/37341-37343 37364-37366 38024 380267.952274030004205e-20 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/450/3855?format=asciiOpticalInfrareddefaultJ/MNRAS/450/3855/table56dat.Positions and photometry (table 5) and derived parameters (table 6)of all 1073 objectsDMP16Dispersion measure (16th percentile)phys.dispMeasure;instr.dispersionfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVPHASVPHAS IDmeta.id;meta.mainintMSPIDMSP ID (Cl* Westerlund 2 MSP NNN in Simbad)meta.idcharVAID? Vargas Alvarez et al. (2013, Cat. J/AJ/145/125, [VKB2013] NNNN in Simbad)meta.idintnullableTFTID? Tsujimoto et al. ID (2007, Cat. J/ApJ/665/719) [TFT2007] NNN in Simbad)meta.idintnullableSIMBADSimbad IDmeta.idcharSpTypeSpectral typesrc.spTypecharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainrmagVPHAS r magnitudemagphot.mag;em.opt.Rfloate_rmagrms uncertainty on rmagmagstat.error;phot.mag;em.opt.RfloatgmagVPHAS g magnitudemagphot.mag;em.opt.Bfloate_gmagrms uncertainty on gmagmagstat.error;phot.mag;em.opt.BfloatumagVPHAS u magnitudemagphot.mag;em.opt.Ufloate_umagrms uncertainty on umagmagstat.error;phot.mag;em.opt.UfloatimagVPHAS i magnitudemagphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.mag;em.opt.IfloatHamag? VPHAS H{alpha} magnitudemagphot.flux;em.line.Halphafloatnullablee_Hamag? rms uncertainty on Hamagmagstat.error;phot.mag;em.IR.HfloatnullableJmagPublished J magnitudemagphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.mag;em.IR.JfloatHmagPublished H magnitudemagphot.mag;em.IR.Hfloate_Hmagrms uncertainty on Hmagmagstat.error;phot.mag;em.IR.HfloatKmagPublished K magnitudemagphot.mag;em.IR.Kfloate_Kmagrms uncertainty on Kmagmagstat.error;phot.mag;em.IR.KfloatlogTeffP16Effective temperature 16th percentilelog(K)phys.temperature.effectivefloatlogTeffmedMedian eEffective temperature (50th percentile)log(K)phys.temperature.effectivefloatlogTeffp84Effective temperature 84th percentilelog(K)phys.temperature.effectivefloatA0P16monochromatic extinction at 4595{AA} (16th percentile)magphys.absorptionfloatA0medMedian monochromatic extinction at 4595{AA} (50th percentile)magphys.absorptionfloatA0P84monochromatic extinction at 4595{AA} (84th percentile)magphys.absorptionfloatRVP16Ratio of total to selective extinction (16th percentile)phys.absorptionfloatRVmedMedian ratio of total to selective extinction (50th percentile)phys.absorptionfloatRVP84Ratio of total to selective extinction (84th percentile)phys.absorptionfloatDMmedMedian dispersion measure (50th percentile)meta.notefloatDMP84Dispersion measure (84th percentile)phys.dispMeasure;instr.dispersionfloatchi2chi^2^ valuestat.fit.chi2;stat.valuedoubleNotesNotes (1)meta.notechar