J/ApJ/897/53ivo://CDS.VizieR/J/ApJ/897/53doi:10.26093/cds/vizier.18970053CDSRetes-Romero R.Mayya Y.D.Luna A.Carrasco L.2022-03-10T07:23:04Z2021-10-12T07:10:45ZCDS support team

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

cds-question@unistra.frinterstellar-mediumstar-forming-regionsyoung-stellar-objectsmolecular-cloudsEver since their discovery, infrared dark clouds (IRDCs) are generally considered to be the sites just at the onset of high-mass (HM) star formation. In recent years, it has been realized that not all IRDCs harbor HM young stellar objects (YSOs). Only those IRDCs satisfying a certain mass-size criterion, or equivalently above a certain threshold density, are found to contain HMYSOs. In all cases, IRDCs provide ideal conditions for the formation of stellar clusters. In this paper, we study the massive stellar content of IRDCs to readdress the relation between IRDCs and HM star formation. For this purpose, we have identified all IRDCs associated with a sample of 12 Galactic molecular clouds (MCs). The selected MCs have been the target of a systematic search for YSOs in an earlier study. The cataloged positions of YSOs have been used to search all YSOs embedded in each identified IRDC. In total, we have found 834 YSOs in 128 IRDCs. The sample of IRDCs have mean surface densities of 319M{odot}/pc^2^, mean mass of 1062M{odot}, and a mass function power-law slope -1.8, which are similar to the corresponding properties for the full sample of IRDCs and resulting physical properties in previous studies. We find that all those IRDCs containing at least one intermediate to HM young star satisfy the often-used mass-size criterion for forming HM stars. However, not all IRDCs satisfying the mass-size criterion contain HM stars. We find that the often-used mass-size criterion corresponds to 35% probability of an IRDC forming a massive star. Twenty-five (20%) of the IRDCs are potential sites of stellar clusters of mass more than 100M{odot}.2020ApJ...897...53Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/897/53CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)J/A+AS/115/81 : A CS(2-1) survey of UC HII regions (Bronfman+, 1996)J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)J/A+A/426/97 : SIMBA survey. 1.2-mm/IRAS sources (Faundez+, 2004)J/ApJ/641/389 : Millimetric observations of IRDC cores (Rathborne+, 2006)J/ApJ/653/1325 : Galactic distribution of infrared dark clouds (Simon+, 2006)J/A+A/462/L17 : Dense cores in interstellar molecular clouds (Alves+, 2007)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/A+A/505/405 : A catalogue of Spitzer dark clouds (Peretto+, 2009)J/ApJ/698/324 : Spitzer IRDCs (Ragan+, 2009)J/ApJ/699/1153 : Kinematic distances GRS molecular clouds (Roman-Duval+, 2009)J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)J/A+A/533/A109 : Pisa pre-main sequence tracks and isochrones (Tognelli+, 2011)J/AJ/144/192 : Spitzer survey of Orion A & B. I. YSO catalog (Megeath+, 2012)J/A+A/559/A79 : IRDC APEX/SABOCA observations (Ragan+, 2013)J/A+A/588/A29 : Star formation in massive clumps in Milky Way (Heyer+, 2016)J/ApJ/822/59 : BGPS. XIV. Molecular cloud clumps GBT obs. (Svoboda+, 2016)J/ApJ/839/113 : Molecular clouds with GLIMPSE/MIPSGAL (Retes-Romero+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/897/53https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/897/53http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/897/53https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/897/53https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/897/53http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/897/53GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/897/53/table1 (Summary of the properties of the MC where IRDCs have been searched)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/897/53/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/897/53/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/897/53/table1?GETtext/xml+votable180.050000true291.322415.20440.005555555555555556Cone search capability for table J/ApJ/897/53/table2 (Observed and derivated parameters of individual IRDCs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/897/53/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/897/53/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/897/53/table2?GETtext/xml+votable180.050000true291.42329215.0209010.0055555555555555566/29504-29505 29507 29510 30599 30604-30605 30622-30623 30695https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/897/53?format=asciidefaultJ/ApJ/897/53/table1Summary of the properties of the MC where IRDCs have been searchedSimbadNameSimbad column added by the CDSmeta.idcharnullableIRASName of the principal IRAS source in the MCmeta.id.assoccharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMCName of the molecular cloudmeta.id;meta.maincharprimaryGLON[16.94/50.28] Galactic longitudedegpos.galactic.lonGLAT[-0.61/0.15] Galactic latitudedegpos.galactic.latDist[1.0/5.4] Kinematical distance (1)kpcpos.distancefloate_Dist[0.1/0.6] Uncertainty in Dist; 12% of valuekpcstat.errorfloatMass[0.23/13.52] Mass of the MC obtained using the LTE methodsolMassphys.massfloate_Mass[0.11/6.46] Uncertainty in MasssolMassstat.error;phys.massfloatNyso[14/861] Number, YSOs spatially associated to the MCmeta.numberintNirdc[1/25] Number, IRDCs spatially associated to the MCmeta.numberintSgas[133/816] Surface gas density of the MCsolMass.pc**-2phot.flux.density.sbinte_Sgas[60/410] Uncertainty in SgassolMass.pc**-2stat.errorintSsfr[1.0/26.8] Surface density of star formation rate of the MCsolMass.Myr**-1.pc**-2phys.SFRfloate_Ssfr[0.6/13.5] Uncertainty in SsfrsolMass.Myr**-1.pc**-2stat.errorfloatSFE[0.5/11.9] Star formation efficiency in % units in each cloud.%stat.paramfloate_SFE[0.1/0.7] Uncertainty in SFE%stat.errorfloat_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexedJ/ApJ/897/53/table2Observed and derivated parameters of individual IRDCsSimbadNameSimbad column added by the CDSmeta.idcharnullableIRDCIRDC identifiermeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMCName of the molecular cloudmeta.id.parentcharGLON[16.91/50.43] Galactic longitude, IRDC centroid (1)degpos.galactic.lonGLAT[-0.69/0.24] Galactic latitude, IRDC centroid (1)degpos.galactic.latmaj[6.0/361.5] Major axis size of IRDC (1)arcsecphys.angSizedoublemin[4.3/123.4] Minor axis size of IRDC (1)arcsecphys.angSizedoublePA[-88.0/332.0] Position angle of IRDC (1)degpos.posAngdoubletau[0.37/0.85] mean opacity, Spitzer/IRAC 8um band (1)phys.absorption.coefffloatArea[0.006/54.2] Area of IRDC (2)pc**2phys.areafloate_Area[0.001/13.6] Uncertainty in Areapc**2stat.error;phys.areafloatRad[0.04/4.16] Effective radius of IRDC (2)pcphys.size.radiusfloate_Rad[0.003/0.3] Uncertainty in Radpcstat.errorfloatMass[2/19702] Mass of the IRDC (2)solMassphys.massdoublee_Mass[1/2168] Uncertainty in MasssolMassstat.error;phys.massdoubleSgas[236/543] Surface gas density of IRDC (2)solMass.pc**-2phot.flux.density.sbdoublee_Sgas[25.99/59.8] Uncertainty in SgassolMass.pc**-2stat.errorfloatSsfr[0.013/34.8] Surface density of the star formation rate of the IRDC (2)solMass.Myr**-1.pc**-2phys.SFRfloate_Ssfr[0.005/13.6] Uncertainty in SsfrsolMass.Myr**-1.pc**-2stat.errorfloat_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexed