J/A+A/615/A148ivo://CDS.VizieR/J/A+A/615/A148doi:10.26093/cds/vizier.36150148CDSDamiani F.2020-09-01T13:27:43Z2018-08-22T11:56:34ZCDS support team

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

cds-question@unistra.fropen-star-clusterspre-main-sequence-starsx-ray-sourcesThe low-mass members of OB associations, expected to be a major component of their total population, are in most cases poorly studied because of the difficulty of selecting these faint stars in crowded sky regions. Our knowledge of many OB associations relies on only a relatively small number of massive members. We study here the Sco OB1 association, with the aim of a better characterization of its properties, such as global size and shape, member clusters and their morphology, age and formation history, and total mass. We use deep optical and near-infrared (NIR) photometry from the VPHAS+ and VVV surveys, over a wide area (2.6{deg}x2.6{deg}), complemented by Spitzer infrared (IR) data, and Chandra and XMM-Newton X-ray data. A new technique is developed to find clusters of pre-main sequence M-type stars using suitable color-color diagrams, complementing existing selection techniques using narrow-band H{alpha} photometry or NIR and ultraviolet (UV) excesses, and X-ray data. We find a large population of approximately 4000 candidate low-mass Sco OB1 members whose spatial properties correlate well with those of H{alpha}-emission, NIR-excess, UV-excess, and X-ray detected members, and unresolved X-ray emission. The low-mass population is spread among several interconnected subgroups: they coincide with the HII regions G345.45+1.50 and IC4628, and the rich clusters NGC 6231 and Trumpler 24, with an additional subcluster intermediate between these two. The total mass of Sco OB1 is estimated to be ~8500M_{sun}_. Indication of a sequence of star-formation events is found, from South (NGC 6231) to North (G345.45+1.50). We suggest that the diluted appearance of Trumpler 24 indicates that the cluster is now dissolving into the field, and that tidal stripping by NGC 6231 nearby contributes to the process.2018A&A...615A.148Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/615/A148CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/341 : VPHAS+ DR2 survey (Drew+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/615/A148https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/615/A148http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/615/A148https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/615/A148https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/615/A148http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/615/A148GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/615/A148/tableb2 (XMM-Newton EPIC X-ray sources in Trumpler 24)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/615/A148/tableb2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/615/A148/tableb2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/615/A148/tableb2?GETtext/xml+votable180.050000true253.59279-41.363510.005555555555555556Cone search capability for table J/A+A/615/A148/tableb3 (Optical/NIR photometry for M stars and stars with UV/IR/H{alpha} excess)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/615/A148/tableb3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/615/A148/tableb3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/615/A148/tableb3?GETtext/xml+votable180.050000true253.10967-42.495750.005555555555555556Cone search capability for table J/A+A/615/A148/tableb1 (Chandra ACIS-I X-ray sources in G345.45+1.50)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/615/A148/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/615/A148/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/615/A148/tableb1?GETtext/xml+votable180.050000true254.72007-40.038920.0055555555555555565/10598 6/42383 42396 42398 42405 42416-42417 42419-42420https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/615/A148?format=asciiX-raydefaultJ/A+A/615/A148/tableb2XMM-Newton EPIC X-ray sources in Trumpler 24SimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintXray[385/579] X-ray source numbermeta.idintXMMUXMM source standard Identifier (JHHMMSS.s+DDMMSS)meta.id;meta.maincharRAJ2000Right ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000.0)degpos.eq.dec;meta.mainPosErrPosition errorarcsecstat.error;posfloatCRateX-ray count ratect/ksphot.count;em.X-rayfloate_CRateError on X-ray count ratect/ksstat.errorfloatVPHAS? VPHAS+ (Cat. II/341) identifier (JHHMMSS.s+DDMMSS.s)meta.idcharrmag? VPHAS+ r magnitudemagphot.mag;em.opt.Rfloatnullableg-r? VPHAS+ g-r color indexmagphot.color;em.opt.B;em.opt.Rfloatnullabler-i? VPHAS+ r-i color indexmagphot.color;em.opt.R;em.opt.IfloatnullableJmag? NIR J magnitudemagphot.mag;em.IR.JfloatnullableJ-H? NIR J-H color indexmagphot.color;em.IR.J;em.IR.HfloatnullableH-K? NIR H-K color indexmagphot.color;em.IR.H;em.IR.KfloatnullableJ/A+A/615/A148/tableb3Optical/NIR photometry for M stars and stars with UV/IR/H{alpha} excessSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/12041] Sequential star numbermeta.id;meta.mainintRAJ2000Right ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000.0)degpos.eq.dec;meta.mainVPHASVPHAS+ identifier (JHHMMSS.s+DDMMSS.s)meta.idcharrmag? VPHAS+ r magnitudemagphot.mag;em.opt.Rfloatnullabler-i? VPHAS+ r-i colormagphot.color;em.opt.R;em.opt.Ifloatnullabler-Ha? VPHAS+ r-Halpha colormagphot.color;em.opt.R;em.line.Halphafloatnullableg-r? VPHAS+ g-r color indexmagphot.color;em.opt.B;em.opt.Rfloatnullableu-g? VPHAS+ u-g color indexmagphot.color;em.opt.U;em.opt.BfloatnullableJmag? NIR J magnitudemagphot.mag;em.IR.JfloatnullableJ-H? NIR J-H color indexmagphot.color;em.IR.J;em.IR.HfloatnullableH-K? NIR H-K color indexmagphot.color;em.IR.H;em.IR.KfloatnullableIRexc[Y] IR-excess flagmeta.codecharHaem[Y] H-alpha-emission flagmeta.codecharUVexc[Y] UV-excess flagmeta.codecharJ/A+A/615/A148/tableb1Chandra ACIS-I X-ray sources in G345.45+1.50SimbadNameSimbad column added by the CDSmeta.idcharCXOUChandra source standard Identifier (JHHMMSS.s+DDMMSS)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintXray[1/384] X-ray source numbermeta.idintRAJ2000Right ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000.0)degpos.eq.dec;meta.mainPosErrPosition errorarcsecstat.error;posfloatCRateX-ray count ratect/ksphot.count;em.X-rayfloate_CRateError on X-ray count ratect/ksstat.errorfloatVPHAS? VPHAS+ (Cat. II/341) identifier (JHHMMSS.s+DDMMSS.s)meta.idcharrmag? VPHAS+ r magnitudemagphot.mag;em.opt.Rfloatnullableg-r? VPHAS+ g-r colormagphot.color;em.opt.B;em.opt.Rfloatnullabler-i? VPHAS+ r-i colormagphot.color;em.opt.R;em.opt.IfloatnullableJmag? NIR J magnitudemagphot.mag;em.IR.JfloatnullableJ-H? NIR J-H colormagphot.color;em.IR.J;em.IR.HfloatnullableH-K? NIR H-K colormagphot.color;em.IR.H;em.IR.Kfloatnullable