J/ApJ/833/229ivo://CDS.VizieR/J/ApJ/833/229doi:10.26093/cds/vizier.18330229CDSLee E.J.Miville-Deschenes M.-A.Murray N.W.2017-07-17T11:40:25Z2017-06-12T12:02:58ZCDS support team

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

cds-question@unistra.frmolecular-cloudsgalaxy-kinematicsco-line-emissioninterstellar-mediumStar formation on galactic scales is known to be a slow process, but whether it is slow on smaller scales is uncertain. We cross-correlate 5469 giant molecular clouds (GMCs) from a new all-sky catalog with 256 star-forming complexes (SFCs) to build a sample of 191 SFC-GMC complexes-collections of multiple clouds each matched to 191 SFCs. The total mass in stars harbored by these clouds is inferred from WMAP free-free fluxes. We measure the GMC mass, the virial parameter, the star formation efficiency {epsilon} and the star formation rate per freefall time {epsilon}_ff_. Both {epsilon} and {epsilon}_ff_ range over 3-4 orders of magnitude. We find that 68.3% of the clouds fall within {sigma}_log{epsilon}_=0.79+/-0.22dex and {sigma}_log{epsilon}_ff__=0.91+/-0.22dex about the median. Compared to these observed scatters, a simple model with a time-independent {epsilon}_ff_ that depends on the host GMC properties predicts {sigma}_log{epsilon}_ff__=0.12-0.24. Allowing for a time-variable {epsilon}_ff_, we can recover the large dispersion in the rate of star formation. This strongly suggests that star formation in the Milky Way is a dynamic process on GMC scales. We also show that the surface star formation rate profile of the Milky Way correlates well with the molecular gas surface density profile.2016ApJ...833..229Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/833/229CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/834/57 : MW molecular clouds from ^12^CO (Miville-Deschenes+, 2017)J/ApJ/831/73 : Galactic MCs associated with HII reg. (Vutisalchavakul+, 2016)J/MNRAS/458/3479 : SVM selection of WISE YSO Candidates (Marton+, 2016)J/A+A/588/A29 : Star formation in massive clumps in Milky Way (Heyer+, 2016)J/ApJS/212/2 : GMCs in the 4th Galactic quadrant (Garcia+, 2014)J/ApJ/779/113 : IR photometry of YSOs in the W40 region (Mallick+, 2013)J/A+A/560/A76 : Stellar clusters in the inner Galaxy (Morales+, 2013)J/ApJ/752/146 : Star forming complexes in Galactic WMAP sources (Lee+, 2012)J/ApJ/748/14 : ONC population data from WFI observations (Da Rio+, 2012)J/ApJS/194/12 : Trumpler 16 in the CCCP (Wolk+, 2011)J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)J/ApJ/719/1104 : Massive star forming complexes in GLIMPSE (Rahman+, 2010)J/ApJ/709/424 : HII regions identified with WMAPS and GLIMPSE (Murray+, 2010)J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/ApJ/688/1142 : Star formation in W5: Spitzer observations (Koenig+, 2008)J/A+A/404/223 : 2MASS IR star clusters in the Galaxy (Bica+, 2003)J/ApJ/428/693 : Rosette Nebula and Maddalena Cloud structures (Williams+ 1994)J/A+A/275/67 : Velocity Field of the outer Galaxy (Brand+ 1993)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/833/229https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/833/229http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/833/229https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/833/229https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/833/229http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/833/229GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/833/229/sfcs (SFC-GMC complexes with star formation properties and unmatched clouds more massive than 10^4.75^Msun)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/833/229/sfcs?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/833/229/sfcs?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/833/229/sfcs?GETtext/xml+votable180.050000true248.2165-48.04540.005555555555555556Cone search capability for table J/ApJ/833/229/table1 (*MML16-SFC match (sorted by SFC luminosities))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/833/229/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/833/229/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/833/229/table1?GETtext/xml+votable180.050000true248.692663-47.978360.0055555555555555565/3661 3667 3672 3673 7275 7377 7383 10453 10615 6/1930 3310 14062 14255 14263 14299 14307 14308 14309 14316 14353 14356 14358 14403 14409 14430 14619 14621 14622 14623 14624 14633 14643 14652 14666 14667 14680 14682 14685 14687 14696 14697 14700 14704 14713 14719 15362 15363 15368 15370 15435 22208 22243 22252 22254 23645 28808 28810 28824 28827 28828 28830 28874 28875 28891 28896 28900 28901 28912 28913 28916 28918 28919 28921 28924 29090 29091 29095 29097 29115 29116 29119 29461 29462 29463 29505 29512 29513 29514 29529 30218 30219 30241 30244 30245 30256 30257 30258 30262 30263 30268 30312 30313 30317 30318 30319 30330 30341 30417 30420 30601 30604 30605 30616 30618 30619 30622 30692 30694 30713 30714 30715 30716 30717 37364 37365 37367 37746 37839 37846 37850 37860 37861 37886 37904 37921 37928 38018 39386 41598 41599 41653 41657 41658 41671 41673 41675 41676 41677 41681 41683 41696 41758 41759 41763 41765 41766 41767 41768 41769 41770 41772 41776 41777 41780 41781 41782 41798 41805 41817 41824 42159 42169 42170 42171 42172 42174 42207 42214 42218 42224 42225 42226 42229 42230 42376 42378 42382 42383 42387 42390 42391 42393 42396 42397 42398 42417 42435 42436 42439 42441 42444 42445 42449 42450 42451 42452 42454 42455 42457 42496 42497 42498 42501 42516 43017 43018 43019 43040https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/833/229?format=asciiRadiodefaultJ/ApJ/833/229/sfcsSFC-GMC complexes with star formation properties and unmatched clouds more massive than 10^4.75^MsunQIonizing luminositys**-1phys.luminositydoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSFCno[0/277] SFC record number (1)meta.id;meta.mainintGLONMass-weighted mean galactic longitudedegpos.galactic.lonGLATMass-weighted mean galactic latitudedegpos.galactic.latVmean[-122/110] Mass-weighted mean velocitykm/sphys.veloc;stat.meanfloatSigV[1.2/22.2] Mass-weighted velocity dispersionkm/sphys.veloc.dispersionfloatRang[0.1/1] Geometric mean angular radius (R_ang_) (2)degphys.angSize;stat.meanfloatMaxAxis[0.2/1.3] Maximum eigenvalue of moment of inertia matrix (R_max_)degphys.angSizefloatMinAxis[0.1/1] Minimum eigenvalue of moment of inertia matrix (R_min_)degphys.angSize;srcfloatRgal[0.02/18] Mass-weighted mean galactocentric radius (3)kpcpos.distance;pos.galactocentricfloatDist[0.4/16] Mass-weighted mean kinematic distance (3)kpcpos.distance;pos.heliocentricfloatWco[23.9/9640] Total CO fluxK.km/sphot.fluxdoubleMgas[1580/] Total gas masssolMassphys.massdoubleRad[2/166] Physical radius (1)pcphys.size.radiusfloatSigma[4/696] Gas column density ({Sigma}_g_) (2)solMass.pc**-2phys.columnDensitydoubleSFEbr[/0.4] Star formation efficiency ({epsilon}_br_) (3)phys.mass;arith.ratiodoubleSFRbr[0.0001/1.3] Star formation rate per free-fall time ({epsilon}_ff,br_) (3)phys.SFRdoubletff[1.4/40] Free-fall time ((3{pi}/32G{rho})^0.5^)1e+06yrtime.epochfloataVir[0.2/26] Virial parameter ({alpha}_vir_) (4)stat.fit.paramdouble_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.decnullableindexedJ/ApJ/833/229/table1*MML16-SFC match (sorted by SFC luminosities)GMCno[13/19689] GMC record number (1)meta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGLONgGalactic longitude of GMCdegpos.galactic.lonSigl[0.08/0.7] RMS dispersion in galactic longitude of GMC ({sigma}_l_)degphys.angSizefloatGLATgGalactic latitude of GMCdegpos.galactic.latSigb[0.08/0.6] RMS dispersion in galactic latitude of GMC ({sigma}_b_)degphys.angSize;srcfloatVlsrg[-122/113] LSR velocity centroid of GMCkm/sphys.veloc;pos.lsrfloatSigV[0.8/16] RMS velocity dispersion of GMC ({sigma}_V_)km/sphys.veloc.dispersionfloatDistg[0.4/16] Kinematic distance to GMCkpcpos.distance;pos.heliocentricfloatSFCno[0/277] Matched SFC record number (1)meta.id.crossintprimaryGLONsGalactic longitude of SFCdegpos.galactic.lonGLATsGalactic latitude of SFCdegpos.galactic.latfloatRad[0.01/2.2] Geometric mean radius of SFCdegphys.angSize;stat.meanfloatVlsrs[-122/112] LSR mean velocity of SFCkm/sphys.veloc;pos.lsrfloatExpV[2.7/49] Expansion velocity of SFCkm/sphys.veloc.expansionfloatDists[0.4/16] Kinematic distance to SFCkpcpos.distance;pos.heliocentricfloat_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