J/A+A/692/A226ivo://CDS.VizieR/J/A+A/692/A226doi:10.26093/cds/vizier.36920226CDSKeilmann E.Kabanovic S.Schneider N.Ossenkopf-Okada V.Stutzki J.,Kobayashi M.I.N.Simon R.Buchbender C. Riechers D.Bigiel F.,Tabatabaei F.2025-02-26T20:02:33Z2024-12-18T08:13:01ZCDS support team

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

cds-question@unistra.frgalaxiesinfrared-sourcesinterstellar-mediummolecular-cloudsco-line-emissionUnderstanding the physical properties such as mass, size, and surface mass density of giant molecular clouds or associations (GMCs/GMAs) in galaxies is crucial for gaining deeper insights into the molecular cloud and star formation (SF) processes. We determine these quantities for the Local Group flocculent spiral galaxy M33 using Herschel dust and archival ^12^CO(2-1) data from the IRAM 30m telescope, and compare them to GMC/GMA properties of the Milky Way derived from CO literature data. For M33, we apply the Dendrogram algorithm on a novel 2D dust-derived NH_2_ map at an angular resolution of 18.2" and on the ^12^CO(2-1) data and employ an XCO factor map instead of a constant value. Dust and CO-derived values are similar, with mean radii of ~58pc for the dust and ~68pc for CO, respectively. However, the largest GMAs have a radius of around 150pc, similar to what was found in the Milky Way and other galaxies, suggesting a physical process that limits the size of GMAs. The less massive and smaller M33 galaxy also hosts less massive and lower-density GMCs compared to the Milky Way by an order of magnitude. Notably, the most massive (> a few 10^6^M_{sun}_) GMC population observed in the Milky Way is mainly missing in M33. The mean surface mass density of M33 is significantly smaller than that of the Milky Way and this is attributed to higher column densities of the largest GMCs in the Milky Way, despite similar GMC areas. We find no systematic gradients in physical properties with the galactocentric radius in M33. However, surface mass densities and masses are higher near the center, implying increased SF activity. In both galaxies, the central region contains ~30% of the total molecular mass. The index of the power-law spectrum of the GMC masses across the entire disk of M33 is alpha=2.3+/-0.1 and alpha=1.9+/-0.1 for dust- and CO-derived data, respectively. We conclude that GMC properties in M33 and the Milky Way are largely similar, though M33 lacks high-mass GMCs, for which there is no straightforward explanation. Additionally, GMC properties are only weakly dependent on the galactic environment, with stellar feedback playing a role that needs further investigation.2024A&A...692A.226Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/692/A226CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/688/A171 : Cloud matching in M33. I. (Keilmann+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/692/A226https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/692/A226http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/692/A226https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/692/A226https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/692/A226http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/692/A226GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/692/A226/table1 (GMC properties derived from the Dendrogram leaves in dust)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/692/A226/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/692/A226/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/692/A226/table1?GETtext/xml+votable180.050000true23.559696430.57718190.005555555555555556Cone search capability for table J/A+A/692/A226/table2 (GMC properties derived from the Dendrogram leaves in CO)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/692/A226/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/692/A226/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/692/A226/table2?GETtext/xml+votable180.050000true23.490542830.775640.005555555555555556Cone search capability for table J/A+A/692/A226/list (List of fits maps)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/692/A226/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/692/A226/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/692/A226/list?GETtext/xml+votable180.050000true23.4617730.664570.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/692/A2266/2154-2155 2240-2241https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/692/A226?format=asciiInfraredRadiodefaultJ/A+A/692/A226/table1GMC properties derived from the Dendrogram leaves in dustXposX position offset (G1)arcsecpos.eq.ra;arith.diffdoubleYposY position offset (G1)arcsecpos.eq.dec;arith.diffdoubleAreaAreapc**2phys.areaintRadRadiuspcphys.size.radiusintMassMasssolMassphys.massintDensDensitycm**-3src.densityintSMDSurface mass densitysolMass.pc**-2phot.flux.density.sbintPresPressureK.cm**-3phys.pressuredoubleElongElongationphys.size.axisRatioTempTemperatureKphys.temperaturefloat_RAPositions from offsets (right ascension part)degpos.eq.ra;meta.main_DEPositions from offsets (declination part)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification numbermeta.id;meta.mainintJ/A+A/692/A226/table2GMC properties derived from the Dendrogram leaves in COrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification numbermeta.id;meta.mainintXposX position offset (G1)arcsecpos.eq.ra;arith.diffdoubleYposY position offset (G1)arcsecpos.eq.dec;arith.diffdoubleAreaAreapc**2phys.areaintRadRadiuspcphys.size.radiusintMassMasssolMassphys.massintXCOXCO conversion factorcm**-2.K**-1.km**-1.sarith.factordoubleDensDensitycm**-3src.densityintSNDSurface mass densitysolMass.pc**-2phot.flux.density.sbintPresPressureK.cm**-3phys.pressuredoubleElongElongationphys.size.axisRatioTempTemperatureKphys.temperaturefloatLCOCO luminosityK.km.s**-1.pc**-2phys.luminositydouble_RAPositions from offsets (right ascension part)degpos.eq.ra;meta.main_DEPositions from offsets (declination part)degpos.eq.dec;meta.mainJ/A+A/692/A226/listList of fits mapsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.DateObservation datestime.epoch;obsnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar