J/ApJ/839/113ivo://CDS.VizieR/J/ApJ/839/113doi:10.26093/cds/vizier.18390113CDSRetes-Romero R.Mayya Y.D.Luna A.Carrasco L.2021-01-25T08:52:03Z2018-01-23T11:21:59ZCDS support team

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

cds-question@unistra.frmolecular-cloudsinfrared-photometryyoung-stellar-objectsstellar-massesco-line-emissioninterstellar-mediumWe study the star-formation (SF) law in 12 Galactic molecular clouds with ongoing high-mass star-formation (HMSF) activity, as traced by the presence of a bright IRAS source and other HMSF tracers. We define the molecular cloud (MC) associated with each IRAS source using ^13^CO line emission, and count the young stellar objects (YSOs) within these clouds using GLIMPSE and MIPSGAL 24{mu}m Spitzer databases. The masses for high-luminosity YSOs (L_bol_>10L_{sun}_) are determined individually using pre-main-sequence evolutionary tracks and the evolutionary stages of the sources, whereas a mean mass of 0.5M_{sun}_ was adopted to determine the masses in the low-luminosity YSO population. The star-formation rate surface density ({Sigma}SFR) corresponding to a gas surface density ({Sigma}gas) in each MC is obtained by counting the number of the YSOs within successive contours of ^13^CO line emission. We find a break in the relation between {Sigma}SFR and {Sigma}gas, with the relation being a power law ({Sigma}SFR{propto}{Sigma}gas^N^) with the index N varying between 1.4 and 3.6 above the break. The {Sigma}gas at the break is between 150-360M_{sun}_/pc^2^ for the sample clouds, which compares well with the threshold gas density found in recent studies of Galactic star-forming regions. Our clouds treated as a whole lie between the Kennicutt relation and the linear relation for Galactic and extra-galactic dense star-forming regions. We find a tendency for the high- mass YSOs to be found preferentially in dense regions at densities higher than 1200M_{sun}_/pc^2^ (~0.25g/cm^2^).2017ApJ...839..113Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/839/113CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)II/332 : c2d Spitzer final data release (DR4) (Evans+, 2003)II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)VII/114 : Massachusetts-Stony Brook Galactic Plane CO Survey (Clemens+ 1986)VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)J/ApJS/91/347 : A 5-GHz VLA Survey of the Galactic Plane (Becker+ 1994)J/ApJS/91/659 : Ultracompact HII regions radio images (Kurtz+ 1994)J/MNRAS/276/57 : IRAS Galactic star-forming regions. II. (Codella+ 1995)J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)J/A+AS/115/81 : A CS(2-1) survey of UC HII regions (Bronfman+, 1996)J/A+A/327/325 : Distances of molecular cloud (May+, 1997)J/MNRAS/291/261 : Methanol maser of IRAS-selected sources (Walsh+ 1997)J/MNRAS/301/640 : Ultracompact H II regions studies. II. (Walsh+, 1998)J/A+A/426/97 : SIMBA survey. 1.2-mm/IRAS sources (Faundez+, 2004)J/ApJ/638/293 : 1.1mm sources in the Perseus Molecular Cloud (Enoch+, 2006)J/ApJ/676/427 : MIPS and IRAC data on ChaII PMS stars (Alcala+, 2008)J/ApJ/674/336 : Spitzer observations of NGC 1333 (Gutermuth+, 2008)J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)J/A+A/501/539 : RMS survey. 6cm observations of YSOs (Urquhart+, 2009)J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)J/ApJ/723/915 : BLAST view of Aquila region (Rivera-Ingraham+, 2010)J/A+A/533/A109 : Pisa pre-main sequence tracks & isochrones (Tognelli+, 2011)J/AJ/144/31 : Spitzer+2MASS photom. of protostar cand. (Kryukova+, 2012)J/AJ/144/192 : Spitzer survey of Orion A & B. I. YSOs (Megeath+, 2012)J/A+A/559/A79 : IRDC APEX/SABOCA observations (Ragan+, 2013)J/ApJS/220/11 : SEDs of Spitzer YSOs in the Gould Belt (Dunham+, 2015)J/AJ/149/64 : MIPSGAL 24{mu}m point source catalog (Gutermuth+, 2015)J/ApJ/806/231 : MISFITS survey: HCO+ obs. of Spitzer YSOs (Heiderman+, 2015)J/ApJ/813/25 : YSO candidates in W49 observed with Spitzer (Saral+, 2015)J/A+A/588/A29 : Star formation in massive clumps in Milky Way (Heyer+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/839/113https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/839/113http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/839/113https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/839/113https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/839/113http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/839/113GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/839/113/table4 (Photometric and physical properties of the YSOs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/839/113/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/839/113/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/839/113/table4?GETtext/xml+votable180.050000true291.40925815.13774780.005555555555555556Cone search capability for table J/ApJ/839/113/gmc (Galactic molecular clouds properties from litterature and derived physical properties (tables 1 and 2))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/839/113/gmc?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/839/113/gmc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/839/113/gmc?GETtext/xml+votable180.050000true291.322415.20440.0055555555555555565/7376 6/29508 29510 30598 30599 30604 30605 30622 30623 306956.772611666688002e-21 6.185923063528282e-20https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/839/113?format=asciiInfraredRadiodefaultJ/ApJ/839/113/table4Photometric and physical properties of the YSOsSimbadNameSimbad column added by the CDSmeta.idchare_3.6mag[0.02/0.4]? Uncertainty in 3.6magmagstat.errorfloatnullable3.6mag[6.7/15.3]? Spitzer/IRAC 3.6um magnitude (2)magphot.mag;em.IR.3-4umfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGMCMolecular cloud name (1)meta.id.parentcharNameMIPSGAL/GLIMPSE YSO identifier (1)meta.id;meta.maincharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.lat4.5mag[6/14.6]? Spitzer/IRAC 4.5um magnitude (2)magphot.mag;em.IR.4-8umfloatnullablee_4.5mag[0.02/0.4]? Uncertainty in 4.5magmagstat.errorfloatnullable5.8mag[4/16]? Spitzer/IRAC 5.8um magnitude (2)magphot.flux.density;em.IR.4-8umfloatnullablee_5.8mag[0.02/1.2]? Uncertainty in 5.8magmagstat.errorfloatnullable8.0mag[4/13.5]? Spitzer/IRAC 8.0um magnitude (2)magphot.flux.density;em.IR.8-15umfloatnullablee_8.0mag[0.02/0.3]? Uncertainty in 8.0magmagstat.errorfloatnullable24mag[-0.9/10.3]? Spitzer/MIPS 24um magnitude (3)magphot.flux.density;em.IR.15-30umfloatnullablee_24mag[0/0.6]? Uncertainty in 24magmagstat.errorfloatnullableC[0/3] IR spectral classification (4)meta.code.classintlogbeta[-3.3/-1.3]? Log {beta} value (5)phys.luminosity;arith.ratiofloatnullablelogLb[-1.3/6.3]? Log bolometric luminosity (6)log(solLum)phys.luminosityfloatnullableMass[0.5/37]? Mass (6)solMassphys.massfloatnullableH[-1/1]? Flag indicating whether YSO has high luminosity (7)meta.codeintnullableSCatDisplay data from GLIMPSE (II/293) and MIPSGAL 24um catalog (Gutermuth+, 2015, J/AJ/149/64) within 1"meta.ref.urlchar_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/839/113/gmcGalactic molecular clouds properties from litterature and derived physical properties (tables 1 and 2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNymeta.numberintnullableGMCName of the molecular cloud containing the IRAS sourcemeta.id.parentcharIRASIRAS name (HHMMm+DDMM; B1950)meta.id;meta.maincharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latSize1Angular Size of the cloudarcminphys.angSizeintSize2Angular Size of the cloudarcminphys.angSizeintLiras[0.7/65.1] Bolometric luminosity (1)1000solLumphys.luminosityfloate_Liras[0.2/20.3] Liras uncertainty (1)1000solLumstat.errorfloatVlsr[-4/67] Velocity with respect to the Local Standard of Rest of the CS source (2)km/sphys.veloc;pos.lsrfloatDelV[2/8] Line width (2)km/sspect.line.widthfloatDist[1/5.4] Kinematical distance (3)kpcpos.distance;pos.heliocentricfloate_Dist[0.1/0.6] Dist uncertaintykpcstat.errorfloatScale[0.2/1.6] Physical scale for an angular scale of 1'pc/arcmininstr.scalefloatArea[15/386] Physical area of the cloud (4)pc**2phys.areaintBeam[0.2/1.2] Physical size of the 46" ^13^CO beam at the distance of the cloudpcpos.distance;instr.beamfloatV13CO[-5/66] Peak velocity of the ^13^CO obtained in this workkm/sphys.velocfloatDelVco[3/11] ^13^CO line width obtained in this workkm/sspect.line.widthfloatNH2[1/7] Molecular hydrogen column density determined from the ^13^CO line1e+22cm**-2phys.columnDensity;spect.linefloate_NH2[0.4/5] NH2 uncertainty1e+22cm**-2stat.error;phys.columnDensityfloatAv[11/72] Visual extinction equivalent to the derived gas column densitymagphys.columnDensityfloate_Av[5/33] Av uncertaintymagstat.errorfloatMvir[0.3/16.1] Cloud mass calculated using virial equilibrium (see Equation (1))10000solMassphys.mass;meta.modelledfloate_Mvir[0.2/14] Mvir uncertainty10000solMassstat.errorfloatMlte[0.2/13.6] Cloud mass calculated using local thermodynamical equilibrium (see Equation (2))10000solMassphys.mass;pos.lsr;pos.lgfloate_Mlte[0.1/7] Mlte uncertainty10000solMassstat.errorfloatMxf[0.3/20] Cloud mass calculated using the X-factor (see Equation (4))10000solMassphys.massfloate_Mxf[0.2/10] Mxf uncertainty10000solMassstat.errorfloatICatDisplay data from Faundez+, 2004, J/A+A/426/97 and Bronfman+, 1996, J/A+AS/115/81meta.ref.urlintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_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