J/ApJ/770/1ivo://CDS.VizieR/J/ApJ/770/1doi:10.26093/cds/vizier.17700001CDSAlexander M.J.Kobulnicky H.A.Kerton C.R.Arvidsson K.2017-06-12T08:24:48Z2015-01-28T07:31:05ZCDS support team

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

cds-question@unistra.frinfrared-photometryyoung-stellar-objectsh-ii-regionsWe present a study of the star formation (SF) region G38.9-0.4 using publicly available multiwavelength Galactic plane surveys from ground- and space-based observatories. This region is composed of four bright mid-IR bubbles and numerous infrared dark clouds. Two bubbles, N 74 and N 75, each host a star cluster anchored by a single O9.5V star. We identified 162 young stellar objects (YSOs) and classify 54 as stage I, 7 as stage II, 6 as stage III, and 32 as ambiguous. We do not detect the classical signposts of triggered SF, i.e., star-forming pillars or YSOs embedded within bubble rims. We conclude that feedback-triggered SF has not occurred in G38.9-0.4. The YSOs are preferentially coincident with infrared dark clouds. This leads to a strong correlation between areal YSO mass surface density and gas mass surface density with a power law slope near 1.3, which closely matches the Schmidt-Kennicutt Law. The correlation is similar inside and outside the bubbles and may mean that the SF efficiency is neither enhanced nor suppressed in regions potentially influenced by stellar feedback. This suggests that gas density, regardless of how it is collected, is a more important driver of SF than stellar feedback. Larger studies should be able to quantify the fraction of all SF that is feedback-triggered by determining the fraction SF, feedback-compressed gas surrounding H II regions relative to that already present in molecular clouds.2013ApJ...770....1Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/770/1CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/MNRAS/424/2442 : Catalog of bubbles from Milky Way Project (Simpson+, 2012)J/ApJ/755/20 : YSOs population of Sh2-294 with Spitzer/IRAC (Samal+, 2012)J/ApJ/715/310 : Early stages of star formation in IRDCs (Rathborne+, 2010)J/ApJ/712/797 : YSOs in Vul OB1 association (Billot+, 2010)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/AJ/136/2413 : Galactic midplane Spitzer red sources (Robitaille+, 2008)J/AJ/136/18 : LMC SAGE. New candidate YSOs (Whitney+, 2008)J/A+A/487/253 : The RMS survey: ^13^CO observations of YSOs (Urquhart+ 2008)J/ApJ/649/759 : Bubbles in the galactic disk (Churchwell+, 2006)J/ApJ/635/560 : New star clusters in the GLIMPSE survey (Mercer+ 2005)J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/770/1https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/770/1http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/770/1https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/770/1https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/770/1http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/770/1GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/770/1/yso (Candidate YSOs parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/770/1/yso?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/770/1/yso?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/770/1/yso?GETtext/xml+votable180.050000true285.99160784.95933520.0055555555555555566/30421 304236.772611666688002e-21 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/770/1?format=asciiInfrareddefaultJ/ApJ/770/1/ysoCandidate YSOs parameterschi2[0/8] The {chi}^2^ of the best fit modelstat.param;meta.modelledfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/162] YSO running sequence numbermeta.idintprimarySSTGLMCIdentifier from the GLIMPSE survey (GLLL.llll+BB.bbbb)meta.id;meta.maincharGLON[38.77/39.1] Galactic longitudedegpos.galactic.lonGLAT[-0.7/-0.2] Galactic latitudedegpos.galactic.latJmag? J band magnitude, from 2MASS or UKIDSS (1)magphot.mag;em.IR.JfloatnullableHmag? H band magnitude, from 2MASS or UKIDSS (1)magphot.mag;em.IR.HfloatnullableKmag? Ks band magnitude, from 2MASS or UKIDSS (1)magphot.mag;em.IR.Kfloatnullable[3.6]Spitzer/IRAC 3.6 micron band magnitudemagphot.mag;em.IR.3-4umfloat[4.5]Spitzer/IRAC 4.5um band magnitudemagphot.mag;em.IR.4-8umfloat[5.8]? Spitzer/IRAC 5.8 micron band magnitudemagphot.flux.density;em.IR.4-8umfloatnullable[8.0]? Spitzer/IRAC 8.0 micron band magnitudemagphot.flux.density;em.IR.8-15umfloatnullable[24]Spitzer/MIPS 24um band magnitudemagphot.flux.density;em.IR.15-30umfloatUGPSCross-match within 0.5" with UKIDSS-GPS DR6 (Cat. II/316)meta.ref.urlintnullable2MCross-match within 1.5" with 2MASS (Cat. II/246)meta.ref.urlintnullableBands[013] Bands used in the fits (2)meta.codecharFitsNumber of acceptable fitsmeta.numberintM*B[0.1/9.2] Best fit stellar masssolMassphys.massfloatM*A[0.6/8.8] Average fit stellar masssolMassphys.massfloatlogMdB[-7.7/-0.5] Best fit log disk masslog(solMass)phys.massfloatlogMdA[-7.7/-0.9] Average fit log disk masslog(solMass)phys.massfloatlogAcB[-8.3/-2.6]? Best fit log accretion ratelog(solMass.yr**-1)phys.mass.lossfloatnullablelogAcA[-9.8/-3.3]? Average fit log accretion ratelog(solMass.yr**-1)phys.mass.lossfloatnullableStgBBest fit integer stage (I, II or III)src.classnullableStgAAverage fit integer stage (I, II or III)src.classnullableFstg[1/3] Average fractional stagesrc.classfloate_Fstg[0/0.7] Dispersion in Fstgstat.errorfloatSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexed