J/ApJ/824/29ivo://CDS.VizieR/J/ApJ/824/29doi:10.26093/cds/vizier.18240029CDSStephens I.W.Jackson J.M.Whitaker J.S.Contreras Y.Guzman A.E.,Sanhueza P.Foster J.B.Rathborne J.M.2018-06-28T06:51:49Z2016-09-26T09:33:59ZCDS support team

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

cds-question@unistra.frinterstellar-mediumradio-astronomysurveysmolecular-cloudsh-ii-regionsinfrared-sourcesIn a survey of 65 galaxies, Gao & Solomon (2004ApJS..152...63G) found a tight linear relation between the infrared luminosity (L_IR_, a proxy for the star formation rate) and the HCN(1-0) luminosity (L_HCN_). Wu et al. (2005ApJ...635L.173W) found that this relation extends from these galaxies to the much less luminous Galactic molecular high-mass star-forming clumps (~1pc scales), and posited that there exists a characteristic ratio L_IR_/L_HCN_ for high-mass star-forming clumps. The Gao-Solomon relation for galaxies could then be explained as a summation of large numbers of high-mass star-forming clumps, resulting in the same L_IR_/L_HCN_ ratio for galaxies. We test this explanation and other possible origins of the Gao-Solomon relation using high-density tracers (including HCN(1-0), N_2_H^+^(1-0), HCO^+^(1-0), HNC(1-0), HC_3_N(10-9), and C_2_H(1-0)) for ~300 Galactic clumps from the Millimetre Astronomy Legacy Team 90GHz (MALT90) survey. The MALT90 data show that the Gao-Solomon relation in galaxies cannot be satisfactorily explained by the blending of large numbers of high-mass clumps in the telescope beam. Not only do the clumps have a large scatter in the L_IR_/L_HCN_ ratio, but also far too many high-mass clumps are required to account for the Galactic IR and HCN luminosities. We suggest that the scatter in the L_IR_/L_HCN_ ratio converges to the scatter of the Gao-Solomon relation at some size-scale >~1kpc. We suggest that the Gao-Solomon relation could instead result from of a universal large-scale star formation efficiency, initial mass function, core mass function, and clump mass function.2016ApJ...824...29Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/824/29CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)J/ApJ/815/130 : High-mass molecular clumps from MALT90 (Guzman+, 2015)J/AJ/148/124 : Herschel key program Heritage (Seale+, 2014)J/A+A/568/A41 : ATLASGAL Compact Source Catalog: 280<l<60 (Urquhart+, 2014)J/A+A/565/A75 : ATLASGAL Dust condensations in Galactic plane (Csengeri+, 2014)J/ApJ/783/130 : Parallaxes of high mass star forming regions (Reid+, 2014)J/ApJ/780/173 : Masses of giant molecular clouds in MW (Battisti+, 2014)J/ApJ/777/157 : 90GHz obs. of high-mass star-forming regions (Hoq+, 2013)J/AJ/146/62 : HERschel HERITAGE in Magellanic Clouds (Meixner+, 2013)J/A+A/549/A45 : ATLASGAL Compact Source Catalog: 330<l<21 (Contreras+, 2013)J/ApJS/197/25 : MALT90 pilot survey (Foster+, 2011)J/ApJS/184/172 : High- and intermediate-mass YSOs in the LMC (Gruendl+, 2009)J/ApJS/178/56 : CO observations of LMC Giant Molecular clouds (Fukui+, 2008)J/ApJ/674/172 : Oxygen abundances of LIRGs and ULIRGs (Rupke+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/824/29https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/824/29http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/824/29https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/824/29https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/824/29http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/824/29GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/824/29/table4 (*IR and molecular fluxes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/824/29/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/824/29/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/824/29/table4?GETtext/xml+votable180.050000true266.93927-29.025810.0055555555555555565/7229 10413 10444 10542 10543 10556 10615 10624 6/28808 28809 28812 28813 28814 28824 28827 28828 28830 28831 28852 28874 28896 28897 28900 28901 28912 28913 28915 29090 29091 29094 29097 29100 29101 29103 29112 29113 29115 29510 41595 41597 41657 41658 41660 41661 41671 41673 41675 41676 41677 41678 41681 41682 41683 41684 41685 41688 41697 41758 41759 41762 41763 41766 41767 41769 41770 41772 41780 41781 41799 41801 41802 41804 41805 41807 41809 41811 41813 41814 41815 41816 41817 41820 41824 41825 42158 42159 42207 42210 42211 42213 42214 42215 42216 42228 42229 42376 42378 42379 42381 42382 42387 42390 42391 42392 42393 42396 42397 42398 42434 42435 42436 42438 42439 42440 42441 42444 42445 42447 42450 42451 42454 42455 42456 42457 42500 42501 42502 42512 43013 43014 43015 43021 43024 43026https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/824/29?format=asciiRadioInfrareddefaultJ/ApJ/824/29/table4*IR and molecular fluxesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAGALATLASGAL identifier (LLL.lll+BB.bbb; G) (1)meta.id;meta.maincharm_AGALComponent identifier (if _A or _B) (2)meta.code.multipcharClassMid-IR classification (3)src.classcharDist[0.06/24]? Distance (4)kpcpos.distance;pos.heliocentricfloatnullablelogFIR[1.5/5] Log IR flux (5)log(solLum.kpc**-2)phot.flux.density;em.IRfloatFHCO+[-0.6/1.7]? Log HCO^+^ line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFHNC[-0.4/1.4]? Log HNC line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFN2H+[-0.7/1.3]? Log N_2_H^+^ line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFHCN[-0.5/1.8]? Log HCN line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFH13CO+[-0.2/0.7]? Log H^13^CO^+^ line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFHN13C[-0.3/0.7]? Log HN^13^C line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableF13CS[-0.2/0.7]? Log ^13^CS line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFHNCO4[-0.08/0.8]? Log HNCO4_0,4_ line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFCH3CN[-0.4/1.1]? Log CH_3_CN line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFSiO[-0.7/0.7]? Log SiO line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFHC3N[-0.6/1.5]? Log HC_3_N line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableFC2H[-0.2/1.1]? Log C_2_H line fluxlog(K.km.s**-1.pc**2.kpc**-2)phot.fluxfloatnullableG15Display data from Guzman+, 2015, J/ApJ/815/130meta.ref.urlintnullableIRASDisplay IRAS PSC data (II/125) within 18"meta.ref.urlcharSimbadLink to the ATLASGAL smm source in SIMBADmeta.ref.urlchar_GlonPositions from ATLASGLAL names (longitude part)degpos.galactic.lon_GlatPositions from ATLASGLAL names (latitude part)degpos.galactic.lat_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