J/ApJ/880/127ivo://CDS.VizieR/J/ApJ/880/127doi:10.26093/cds/vizier.18800127CDSJimenez-Donaire M.J.Bigiel F.Leroy A.K.Usero A.Cormier D.,Puschnig J.Gallagher M.Kepley A.Bolatto A.Garcia-Burillo S.,Hughes A.Kramer C.Pety J.Schinnerer E.Schruba A.Schuster K.,Walter F.2021-07-05T06:54:51Z2021-02-01T08:00:55ZCDS support team

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

cds-question@unistra.frgalaxiesinterstellar-mediumradio-astronomymolecular-physicsWe present EMPIRE, an IRAM 30m large program that mapped {lambda}=3-4mm dense gas tracers at ~1-2kpc resolution across the whole star-forming disk of nine nearby massive spiral galaxies. We describe the EMPIRE observing and reduction strategies and show new whole-galaxy maps of HCN(1-0), HCO^+^(1-0), HNC(1-0), and CO(1-0). We explore how the HCN-to-CO and IR-to-HCN ratios, observational proxies for the dense gas fraction and dense gas star formation efficiency, depend on host galaxy and local environment. We find that the fraction of dense gas correlates with stellar surface density, gas surface density, molecular-to-atomic gas ratio, and dynamical equilibrium pressure. In EMPIRE, the star formation rate per unit dense gas is anticorrelated with these same environmental parameters. Thus, although dense gas appears abundant in the central regions of many spiral galaxies, this gas appears relatively inefficient at forming stars. These results qualitatively agree with previous work on nearby galaxies and the Milky Way's Central Molecular Zone. To first order, EMPIRE demonstrates that the conditions in a galaxy disk set the gas density distribution and that the dense gas traced by HCN shows an environment-dependent relation to star formation. However, our results also show significant (+/-0.2dex) galaxy-to-galaxy variations. We suggest that gas structure below the scale of our observations and dynamical effects likely also play an important role.2019ApJ...880..127Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/880/127CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/237 : HYPERLEDA. I. Catalog of galaxies (Paturel+, 2003)J/AJ/136/2782 : Star formation efficiency in nearby galaxies (Leroy+, 2008)J/AJ/136/2563 : HI Nearby Galaxy Survey, THINGS (Walter+, 2008)J/ApJ/703/517 : The Spitzer Local Volume Legacy: IR photometry (Dale+, 2009)J/ApJ/706/599 : H{alpha} and UV SFR in the local volume (Lee+, 2009)J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)J/ApJS/190/233 : Spectroscopy & abundances of SINGS gal. (Moustakas+, 2010)J/PASP/122/1397 : Spitzer Survey of Stellar Structure in Gal. (Sheth+, 2010)J/A+A/549/A17 : IRAM spectra toward M33 Giant Mol. Clouds (Buchbender+, 2013)J/AJ/146/150 : Velocity dispersions of 12 nearby gal. (Caldu-Primo+, 2013)J/ApJ/805/31 : IR-radio luminosities & surface densities (Liu+, 2015)J/ApJ/824/29 : ATLASGAL clumps with IRAS & MALT90 data (Stephens+, 2016)J/ApJ/831/73 : MCs associated with HII reg. (Vutisalchavakul+, 2016)J/ApJ/846/71 : M51 ISM structures from the CO maps of PAWS (Leroy+, 2017)J/ApJ/835/217 : Density distributions for mm-wave line ratios (Leroy+, 2017)J/ApJ/858/90 : Radial profiles of 5 nearby galaxies (Gallagher+, 2018)J/A+A/610/A77 : Orion Integral Filament N2H+(1-0) data (Hacar+, 2018)J/ApJ/860/172 : Cloud-scale molecular gas properties in 15 gal. (Sun+, 2018)J/A+A/625/A19 : 33GHz continuum map of M51 (Querejeta+, 2019)http://empiresurvey.webstarts.com/ : The EMPIRE survey of dense gas home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/880/127https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/880/127http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/880/127https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/880/127https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/880/127http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/880/127GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/880/127/table1 (EMPIRE galaxy sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/880/127/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/880/127/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/880/127/table1?GETtext/xml+votable180.050000true24.17416715.7833330.0055555555555555566/4511 5715 10841 11027 15592 18398 27861 28035 28167https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/880/127?format=asciiRadiodefaultJ/ApJ/880/127/table1EMPIRE galaxy sampleNGCNGC numbermeta.id;meta.mainintprimaryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.maininc[7/65] Inclination from HyperLedasrc.orbital.inclinationintPA[20/243] Position angle from HyperLedadegpos.posAngintr25[2.5/5.9] Radius of the B-band 25th magnitude isophote from HyperLedaphys.angSizefloatDist[7/16.8] Distance from the Extragalactic Distance Database (Tully+ 2009AJ....138..323T)pcpos.distance;pos.heliocentricfloatVhel[42.4/2407] Heliocentric central velocity from Walter+ (2008, J/AJ/136/2563)km/sspect.dopplerVeloc;pos.heliocentricfloatMetal[8.34/8.68] Metallicity 12+log(O/H) (1)phys.abund.ZfloatMorphMorphological type from NEDsrc.morph.typecharSFR[0.0028/0.021] Average SFR surface density inside 0.75 r_25_ from Leroy+ (2013AJ....146...19L)phys.SFRdoublelogM[10/10.6] Log of integrated stellar mass of the entire galaxy based on 3.6um emission from Dale+ (2007ApJ...655..863D and 2009, J/ApJ/703/517)log(solMass)src.class.starGalaxyfloatNlNumber of line-of-sight measurements for this galaxy (link to Table 9)meta.numberintnullableNpNumber of radial profile measurements for this galaxy (link to Table 10)meta.numberintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharLEDAmeta.ref.urlcharJ/ApJ/880/127/table9Individual line-of-sight measurementsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGC[628/6946] NGC number of the galaxymeta.id.parentintR25[0/1.1] Galactocentric radius normalized to r25phys.size.radius;pos.galactocentric;arith.ratiofloatl_IHCNUpper limit flag (2)meta.code.errorcharIHCN[0.1/6.5]? HCN(1-0) integrated intensity (1)K.km/sphot.flux.densityfloatnullablee_IHCN[0.04/0.2]? Uncertainty in IHCNK.km/sstat.errorfloatnullablel_IHCO+Upper limit flag (2)meta.code.errorcharIHCO+[0.1/5.7]? HCO+(1-0) integrated intensity (1)K.km/sphot.flux.densityfloatnullablee_IHCO+[0.04/0.2]? Uncertainty in IHCO+K.km/sstat.errorfloatnullablel_IHNCUpper limit flag (2)meta.code.errorcharIHNC[0.14/2.1]? HNC(1-0) integrated intensity (1)K.km/sphot.flux.densityfloatnullablee_IHNC[0.07/0.5]? Uncertainty in IHNCK.km/sstat.errorfloatnullablel_I12COUpper limit flag (2)meta.code.errorcharI12CO[0.4/153]? 12CO(1-0) integrated intensity (1)K.km/sphot.flux.densityfloatnullablee_I12CO[0.1/0.8]? Uncertainty in I12COK.km/sstat.errorfloatnullablel_I13COUpper limit flag (2)meta.code.errorcharI13CO[0.14/10.1]? 13CO(1-0) integrated intensity (1)K.km/sphot.flux.densityfloatnullablee_I13CO[0.04/0.4]? Uncertainty in I13COK.km/sstat.errorfloatnullablel_IC18OUpper limit flag (2)meta.code.errorcharIC18O[0/2.7]? C18O(1-0) integrated intensity (1)K.km/sphot.flux.densityfloatnullablee_IC18O[0/0.2]? Uncertainty in IC18OK.km/sstat.errorfloatnullableJ/ApJ/880/127/table11Dense gas literature compilationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference identifier (1)meta.bibcharlogLIR[1.95/13.75] log IR luminositylog(solLum)phys.luminosity;em.IRdoublelogLHCN[-1.11/10.67]? log HCN(1-0) luminositylog(K.km.s**-1.pc**-2)phys.luminosity;em.radiodoublenullableOTType code (2)meta.code.classcharJ/ApJ/880/127/table10Individual radial profilesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCNGC number of the galaxymeta.id.parentintRad[0.58/10.4] Outer edge of stacking radiuskpcphys.size.radiusfloatl_IHCNUpper limit flag (1)meta.code.errorcharIHCN[0.01/3.3]? HCN(1-0) integrated intensityK.km/sphot.flux.densityfloatnullablee_IHCN[0.01/0.09]? Uncertainty in IHCNK.km/sstat.errorfloatnullablel_IHCO+Upper limit flag (1)meta.code.errorcharIHCO+[0.01/2.9]? HCO+(1-0) integrated intensityK.km/sphot.flux.densityfloatnullablee_IHCO+[0/0.07]? Uncertainty in IHCO+K.km/sstat.errorfloatnullablel_IHNCUpper limit flag (1)meta.code.errorcharIHNC[0/1.1]? HNC(1-0) integrated intensityK.km/sphot.flux.densityfloatnullablee_IHNC[0/0.06]? Uncertainty in IHNCK.km/sstat.errorfloatnullableI12CO[1/86.3] 12CO(1-0) integrated intensityK.km/sphot.flux.densityfloate_I12CO[0.05/1.8] Uncertainty in I12COK.km/sstat.errorfloatI13CO[0.07/5.6]? 13CO(1-0) integrated intensityK.km/sphot.flux.densityfloatnullablee_I13CO[0.02/0.3]? Uncertainty in I13COK.km/sstat.errorfloatnullablel_IC18OUpper limit flag (1)meta.code.errorcharIC18O[0.01/1.4]? C18O(1-0) integrated intensityK.km/sphot.flux.densityfloatnullablee_IC18O[0.03/0.1]? Uncertainty in IC18OK.km/sstat.errorfloatnullable