J/ApJ/841/109ivo://CDS.VizieR/J/ApJ/841/109doi:10.26093/cds/vizier.18410109CDSOchsendorf B.B.Meixner M.Roman-Duval J.Rahman M.Evans N.J.2018-05-14T09:10:39Z2018-03-01T15:31:36ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsmolecular-cloudsh-ii-regionsyoung-stellar-objectsco-line-emissioninfrared-sourcesGalactic star formation scaling relations show increased scatter from kpc to sub-kpc scales. Investigating this scatter may hold important clues to how the star formation process evolves in time and space. Here, we combine different molecular gas tracers, different star formation indicators probing distinct populations of massive stars, and knowledge of the evolutionary state of each star-forming region to derive the star formation properties of ~150 star-forming complexes over the face of the Large Magellanic Cloud (LMC). We find that the rate of massive star formation ramps up when stellar clusters emerge and boost the formation of subsequent generations of massive stars. In addition, we reveal that the star formation efficiency of individual giant molecular clouds (GMCs) declines with increasing cloud gas mass (M_cloud_). This trend persists in Galactic star-forming regions and implies higher molecular gas depletion times for larger GMCs. We compare the star formation efficiency per freefall time ({epsilon}_ff_) with predictions from various widely used analytical star formation models. While these models can produce large dispersions in {epsilon}_ff_ similar to those in observations, the origin of the model-predicted scatter is inconsistent with observations. Moreover, all models fail to reproduce the observed decline of {epsilon}_ff_ with increasing M_cloud_ in the LMC and the Milky Way. We conclude that analytical star formation models idealizing global turbulence levels and cloud densities and assuming a stationary star formation rate (SFR) are inconsistent with observations from modern data sets tracing massive star formation on individual cloud scales. Instead, we reiterate the importance of local stellar feedback in shaping the properties of GMCs and setting their massive SFR.2017ApJ...841..109Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/841/109CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/686/948 : CO in extragalactic giant molecular clouds (Bolatto+, 2008)J/ApJS/178/56 : CO observations of LMC Giant Molecular clouds (Fukui+, 2008)J/AJ/136/18 : LMC SAGE. New candidate YSOs (Whitney+, 2008)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/ApJS/184/172 : High- and intermediate-mass YSOs in the LMC (Gruendl+, 2009)J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)J/ApJS/184/1 : Molecular clouds in the LMC by NANTEN. II. (Kawamura+, 2009)J/ApJ/707/1417 : HST view of YSOs in the LMC (Vaidya+, 2009)J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)J/ApJ/709/424 : HII regions identified with WMAPS and GLIMPSE (Murray+, 2010)J/ApJ/723/492 : Physical data of GRS molecular clouds (Roman-Duval+, 2010)J/ApJS/197/16 : CO observations of LMC molecular clouds (MAGMA). (Wong+, 2011)J/ApJ/755/40 : HII regions in the MCs from MCELS (Pellegrini+, 2012)J/AJ/146/62 : HERschel HERITAGE in Magellanic Clouds (Meixner+, 2013)J/ApJ/789/81 : Multiwavelength survey of HII regions in NGC300 (Faesi+, 2014)J/AJ/148/124 : Herschel key program Heritage (Seale+, 2014)J/ApJS/220/11 : SEDs of Spitzer YSOs in the Gould Belt (Dunham+, 2015)J/ApJ/806/231 : MISFITS survey: HCO+ obs. of Spitzer YSOs (Heiderman+, 2015)J/A+A/588/A29 : Star formation in massive clumps in Milky Way (Heyer+, 2016)J/ApJ/833/229 : Star forming cloud-GMC complexes (Lee+, 2016)J/ApJ/831/73 : Galactic MCs with HII regions (Vutisalchavakul+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/841/109https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/841/109http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/841/109https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/841/109https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/841/109http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/841/109GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/841/109/table4 (*MAGMA cloud decomposition with MYSO SFR parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/841/109/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/841/109/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/841/109/table4?GETtext/xml+votable180.050000true80.753-68.3220.005555555555555556Cone search capability for table J/ApJ/841/109/table5 (*MAGMA cloud decomposition with Ha+24um SFR parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/841/109/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/841/109/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/841/109/table5?GETtext/xml+votable180.050000true76.749-70.720.005555555555555556Cone search capability for table J/ApJ/841/109/table6 (*J16 cloud decomposition with MYSO SFR parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/841/109/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/841/109/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/841/109/table6?GETtext/xml+votable180.050000true85.961-71.130.005555555555555556Cone search capability for table J/ApJ/841/109/table7 (*J16 cloud decomposition with Ha+24um SFR parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/841/109/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/841/109/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/841/109/table7?GETtext/xml+votable180.050000true76.331-66.8960.0055555555555555565/8263 8269 8272 8274 8275 8276 8278 8280 6/33047 33051 33092 33094 33095 33116 33124 33126 33127 33128 33129https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/841/109?format=asciiRadioInfrareddefaultJ/ApJ/841/109/table4*MAGMA cloud decomposition with MYSO SFR parametersMass[2440/3.6e+06] Total masssolMassphys.massdoublesigV[0.4/5]? CO velocity dispersion; intensity weighted (only for tables 4 and 5)km/sphys.veloc.dispersion;spect.linedoublenullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/220] Running sequence number (1)meta.id.part;meta.mainintClDCloud decomposition method (1)meta.id.part;meta.maincharSFtSF tracer (1)meta.id.part;meta.maincharRAJ2000[71.8/89] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-72/-65] Declination (J2000)degpos.eq.dec;meta.mainType[1/3] Kawamura+ 2009, J/ApJS/184/1, giant molecular cloud (GMC) type (2)meta.codeintRad[6.8/171] Total radiuspcphys.size.radiusdoubleSFR[0/91200] Star formation rate (3)solMass/Myrphys.SFRdoubleSFE[0/0.5] Star formation 'efficiency'; SFR/M_cloud_Myr**-1stat.paramdoubleSFEff[0/4.7] Star formation efficiency per free fall time; (SFR/M_cloud_)*tffstat.paramdoubletff[5.9/19.7] Free-fall timeMyrtime.epochdoubleJ/ApJ/841/109/table5*MAGMA cloud decomposition with Ha+24um SFR parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/220] Running sequence number (1)meta.id.part;meta.mainintClDCloud decomposition method (1)meta.id.part;meta.maincharSFtSF tracer (1)meta.id.part;meta.maincharDEJ2000[-72/-65] Declination (J2000)degpos.eq.dec;meta.mainType[1/3] Kawamura+ 2009, J/ApJS/184/1, giant molecular cloud (GMC) type (2)meta.codeintMass[2440/3.6e+06] Total masssolMassphys.massdoubleRad[6.8/171] Total radiuspcphys.size.radiusdoubleSFR[0/91200] Star formation rate (3)solMass/Myrphys.SFRdoubleSFE[0/0.5] Star formation 'efficiency'; SFR/M_cloud_Myr**-1stat.paramdoubleSFEff[0/4.7] Star formation efficiency per free fall time; (SFR/M_cloud_)*tffstat.paramdoubletff[5.9/19.7] Free-fall timeMyrtime.epochdoublesigV[0.4/5]? CO velocity dispersion; intensity weighted (only for tables 4 and 5)km/sphys.veloc.dispersion;spect.linedoublenullableRAJ2000[71.8/89] Right Ascension (J2000)degpos.eq.ra;meta.mainJ/ApJ/841/109/table6*J16 cloud decomposition with MYSO SFR parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/220] Running sequence number (1)meta.id.part;meta.mainintClDCloud decomposition method (1)meta.id.part;meta.maincharSFtSF tracer (1)meta.id.part;meta.maincharRAJ2000[71.8/89] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-72/-65] Declination (J2000)degpos.eq.dec;meta.mainType[1/3] Kawamura+ 2009, J/ApJS/184/1, giant molecular cloud (GMC) type (2)meta.codeintMass[2440/3.6e+06] Total masssolMassphys.massdoubleRad[6.8/171] Total radiuspcphys.size.radiusdoubleSFR[0/91200] Star formation rate (3)solMass/Myrphys.SFRdoubleSFE[0/0.5] Star formation 'efficiency'; SFR/M_cloud_Myr**-1stat.paramdoubleSFEff[0/4.7] Star formation efficiency per free fall time; (SFR/M_cloud_)*tffstat.paramdoubletff[5.9/19.7] Free-fall timeMyrtime.epochdoubleJ/ApJ/841/109/table7*J16 cloud decomposition with Ha+24um SFR parametersSFtSF tracer (1)meta.id.part;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/220] Running sequence number (1)meta.id.part;meta.mainintClDCloud decomposition method (1)meta.id.part;meta.maincharRAJ2000[71.8/89] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-72/-65] Declination (J2000)degpos.eq.dec;meta.mainType[1/3] Kawamura+ 2009, J/ApJS/184/1, giant molecular cloud (GMC) type (2)meta.codeintMass[2440/3.6e+06] Total masssolMassphys.massdoubleRad[6.8/171] Total radiuspcphys.size.radiusdoubleSFR[0/91200] Star formation rate (3)solMass/Myrphys.SFRdoubleSFE[0/0.5] Star formation 'efficiency'; SFR/M_cloud_Myr**-1stat.paramdoubleSFEff[0/4.7] Star formation efficiency per free fall time; (SFR/M_cloud_)*tffstat.paramdoubletff[5.9/19.7] Free-fall timeMyrtime.epochdouble