J/ApJ/821/125ivo://CDS.VizieR/J/ApJ/821/125doi:10.26093/cds/vizier.18210125CDSFaesi C.M.Lada C.J.Forbrich J.2018-09-13T06:08:50Z2016-08-29T07:50:36ZCDS support team

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

cds-question@unistra.frmolecular-cloudsradio-astronomymillimeter-astronomysubmillimeter-astronomyWe present the first high angular resolution study of giant molecular clouds (GMCs) in the nearby spiral galaxy NGC 300, based on observations from the Submillimeter Array (SMA). We target eleven 500pc sized regions of active star formation within the galaxy in the ^12^CO(J=2-1) line at 40pc spatial and 1km/s spectral resolution and identify 45 individual GMCs. We characterize the physical properties of these GMCs, and find that they are similar to GMCs in the disks of the Milky Way and other nearby spiral galaxies. For example, the GMC mass spectrum in our sample has a slope of 1.80+/-0.07. Twelve clouds are spatially resolved by our observations, of which ten have virial mass estimates that agree to within a factor of two with mass estimates derived directly from ^12^CO integrated intensity, suggesting that the majority of these GMCs are bound. The resolved clouds show consistency with Larson's fundamental relations between size, linewidth, and mass observed in the Milky Way. We find that the linewidth scales with the size as {Delta}V{propto}R^0.52+/-0.20^, and the median surface density in the subsample is 54M_{sun}_/pc^2^. We detect ^13^CO in four GMCs and find a mean ^12^CO/^13^CO flux ratio of 6.2. Our interferometric observations recover between 30% and 100% of the integrated intensity from the APEX single dish ^12^CO observations of Faesi et al. (2014, J/ApJ/789/81), suggesting the presence of low-mass GMCs and/or diffuse gas below our sensitivity limit. The fraction of APEX emission recovered increases with the SMA total intensity, as well as with the star formation rate.2016ApJ...821..125Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/821/125CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/798/58 : HELGA VI. GMC associations in M31 (Kirk+, 2015)J/ApJ/789/81 : Multiwavelength data of HII regions in NGC 300 (Faesi+, 2014)J/ApJ/772/107 : Giant molecular clouds in nearby gal. (Donovan Meyer+, 2013)J/A+A/542/A108 : Giant molecular clouds in M33 (Gratier+, 2012)J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)J/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/ApJ/661/830 : Giant molecular clouds of M33 (Rosolowsky+, 2007)J/AJ/128/1167 : ARAUCARIA project : NGC 300 Cepheids. II (Gieren+, 2004)J/ApJS/149/343 : Giant molecular clouds in M33 (Engargiola+, 2003)J/ApJ/551/852 : FCRAO CO survey of the outer Galaxy (Heyer+, 2001)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/821/125https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/821/125http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/821/125https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/821/125https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/821/125http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/821/125GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/821/125/table1 (SMA observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/821/125/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/821/125/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/821/125/table1?GETtext/xml+votable180.050000true13.7004583-37.72536110.005555555555555556Cone search capability for table J/ApJ/821/125/table3 (NGC 300 giant molecular cloud (GMC) properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/821/125/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/821/125/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/821/125/table3?GETtext/xml+votable180.050000true13.6178333-37.69819440.0055555555555555566/35536https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/821/125?format=asciiRadioMillimeterdefaultJ/ApJ/821/125/table1SMA observationsPIDProject codemeta.id;obscharNa[5-8] Number of antennasmeta.numbercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observationtime.epochnullable[DCL88]Name of the HII region targetedmeta.id;obs.fieldcharNgmcNumber of giant molecular cloud in this regionmeta.numberintnullableArrayArray configuration ("compact" or "compact-north")phys.atmol.configuration;instr.setupcharDmin[16.4] Minimum baselineminstr.baseline;stat.minfloatDmax[68/140] Maximum baselineminstr.baseline;stat.maxfloat<tau0>[0.06/0.3] Track-averaged zenith opacity at 225GHzphys.absorption.coefffloatTime[171/312] On-source time of observationmintime.epochfloatSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/821/125/table3NGC 300 giant molecular cloud (GMC) propertiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[DCL88]Name of the HII regionmeta.id.parentcharIDCloud identifier within the DCL regionmeta.id;meta.mainintRAJ2000[0] Hour of Right Ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000[37] Degree of Declination (J2000) (1)pos.eq.dec;meta.mainv0[88/181] Best-fit velocity centroidkm/sphys.veloc;meta.modelledfloatamaj[3/11] FWHM major axis length (2)arcsecphys.angSizefloatbmin[1/6] FWHM minor axis length (2)arcsecphys.angSizefloatPA[-78/82] Position angle (3)degpos.posAngintR[8/43]? Physical sizepcphys.size.radiusfloatnullablee_R[1/15]? Uncertainty in R (4)pcstat.errorfloatnullableDelV[1.8/8.3] FWHM linewidthkm/sspect.line.widthfloate_DelV[0.6/6] Uncertainty in DelV (4)km/sstat.errorfloatMlum[0.5/75] Luminous mass10000solMassphys.massfloate_Mlum[0.7/10] Uncertainty in Mlum (4)10000solMassstat.errorfloatMvir[1/41]? Virial mass10000solMassphys.massfloatnullablee_Mvir[2/24]? Uncertainty in Mvir (4)10000solMassstat.errorfloatnullableLCO[601/90600] Total CO(2-1) luminosityK.km.s**-1.pc**2phys.luminosity;em.radiodoublee_LCO[794/11500] Uncertainty in LCO (4)K.km.s**-1.pc**2stat.errordoubleSimbadSimbad column added by the CDSmeta.ref.urlchar