J/MNRAS/476/1213ivo://CDS.VizieR/J/MNRAS/476/1213doi:10.26093/cds/vizier.74761213CDSGetman K.V.Feigelson E.D.Kuhn M.A.Bate M.R.Broos P.S.Garmire G.P.2024-08-18T20:18:22Z2021-05-31T13:27:54ZCDS support team

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

cds-question@unistra.fropen-star-clustersstellar-agesThe pace and pattern of star formation leading to rich young stellar clusters is quite uncertain. In this context, we analyse the spatial distribution of ages within 19 young (median t<=3Myr on the Siess et al. time-scale), morphologically simple, isolated, and relatively rich stellar clusters. Our analysis is based on young stellar object (YSO) samples from the Massive Young Star-Forming Complex Study in Infrared and X-ray and Star Formation in Nearby Clouds surveys, and a new estimator of pre-main sequence (PMS) stellar ages, Age_JX_, derived from X-ray and near-infrared photometric data. Median cluster ages are computed within four annular subregions of the clusters. We confirm and extend the earlier result of Getman et al. (2014ApJ...787..108G, Cat. J/ApJ/787/108; 2014ApJ...787..109G. Cat. J/ApJ/787/109): 80 per cent of the clusters show age trends where stars in cluster cores are younger than in outer regions. Our cluster stacking analyses establish the existence of an age gradient to high statistical significance in several ways. Time-scales vary with the choice of PMS evolutionary model; the inferred median age gradient across the studied clusters ranges from 0.75 to 1.5Myr/pc. The empirical finding reported in the present study - late or continuing formation of stars in the cores of star clusters with older stars dispersed in the outer regions - has a strong foundation with other observational studies and with the astrophysical models like the global hierarchical collapse model of Vazquez-Semadeni et al. (2017MNRAS.467.1313V).2018MNRAS.476.1213Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/476/1213CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/787/108 : Age estimates for massive SFR stellar populationsJ/ApJ/787/109 : Age estimates for NGC 2024 and ONC stars (Getman+, 2014)J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)J/ApJS/229/28 : SFiNCs: X-ray, IR and membership catalogs (Getman+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/476/1213https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/476/1213http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/476/1213https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/476/1213https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/476/1213http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/476/1213GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/476/1213/table2 (AgeJX Stars. All MYStIX and SFiNCs stars with available age estimates across the 19 clusters of interest)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/476/1213/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/476/1213/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/476/1213/table2?GETtext/xml+votable180.050000true274.62952-13.761373060.0055555555555555565/10615 6/1231 1287 1539 3755 14029 14031 14040 15662-15663 15681 15683-15684 15748 21438-21439 21456 22249 22804-22805 22855 29116 29118 29463 30341 30366 37884 37886https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/476/1213?format=asciidefaultJ/MNRAS/476/1213/table2AgeJX Stars. All MYStIX and SFiNCs stars with available age estimates across the 19 clusters of interestrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionStar-forming region name (1)meta.id.parentcharSourceSource name (HHMMSS.ss+DDMMSS.sa) (2)meta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainAgeJXStellar age estimated using the AgeJX method of Getman et al. (2014ApJ...787..108G)Myrtime.agefloat