J/A+A/687/A26ivo://CDS.VizieR/J/A+A/687/A26doi:10.26093/cds/vizier.36870026CDSSaldano H.P.Rubio M.Bolatto A.D.Sandstrom KSwift B.J.Verdugo C.,Jameson K.Walker C.K.Kulesa C.Spilker J.Bergman P.Salazar G.A.2024-11-29T20:03:57Z2024-06-27T07:26:16ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsco-line-emissionradio-astronomyinterstellar-mediumThe Small Magellanic Cloud (SMC) is an ideal laboratory for studying the properties of star-forming regions thanks to its low metallicity, which has an impact on the molecular gas abundance. However, a small number of molecular gas surveys of the entire galaxy have been carried out in the last few years, limiting the measurements of interstellar medium (ISM) properties in a homogeneous manner. We present the CO(3-2) APEX survey at a 6pc resolution of the bar of the SMC, observed with the SuperCAM receiver attached to the APEX telescope. This high-resolution survey has allowed us to study certain properties of the ISM and to identify CO clouds in the innermost parts of the H_2_ envelopes. We adopted the CO analysis in the SMC bar comparing the CO(3-2) survey with that of the CO(2-1) of a similar resolution.We studied the CO(3-2)-to-CO(2-1) ratio (R32), which is very sensitive to the environment properties (e.g., star-forming regions). We analyzed the correlation of this ratio with observational quantities that trace the star formation such as the local CO emission, the Spitzer color [70=160], and the total IR surface brightness measured from the Spitzer and Herschel bands. For the identification of the CO(3-2) clouds, we used the CPROPS algorithm, which allowed us to measure the physical properties of the clouds. We analyzed the scaling relationships of such physical properties. We obtained R_32_=0.65+/-0.02 for the SW bar and a slightly higher ratio, R_32_=0.7+/-0.1; for N66 in the SMC.We found that R_32_ varies from region to region, depending on the star formation activity. In regions dominated by HII and photo-dissociated regions (e.g., N22, N66) R_32) tends to be higher than the median values. Meanwhile, lower values were found toward quiescent clouds.We also found that R_32_ is correlated with the IR color [70/160] and the total IR surface brightness. This finding indicates that R_32_ increases with environmental properties, such as the dust temperature, total gas density, and radiation field. We identified 225 molecular clouds with sizes of R>1.5pc and signal-to-noise ratios (S/N) of >3, of which only 17 are well resolved CO(3-2) clouds with S/N>~5. These 17 clouds follow consistent scaling relationships to the inner Milky Way clouds but with some departures. For instance, CO(3-2) tends to be less turbulent and less luminous than the inner Milky Way clouds of similar sizes. Finally, we estimated a median virial-based CO(3-2)-to-H_2_ conversion factor of 12.6^+10^_-7^M_{sun}_ (K.km/s/pc^2^)^-1^ for the total sample.2024A&A...687A..26Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/687/A26CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/687/A26https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/687/A26http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/687/A26https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/687/A26https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/687/A26http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/687/A26GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/687/A26/table2 (Physical parameters of CO(3-2) clouds in the SMC)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/687/A26/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/687/A26/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/687/A26/table2?GETtext/xml+votable180.050000true10.58175-73.44106390.005555555555555556Cone search capability for table J/A+A/687/A26/list (List of fits files)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/687/A26/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/687/A26/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/687/A26/list?GETtext/xml+votable180.050000true12.078333-73.3015280.0055555555555555566/33293-33295 33306 33316-33317 33328https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/687/A26?format=asciiRadiodefaultJ/A+A/687/A26/table2Physical parameters of CO(3-2) clouds in the SMCrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDCloud numbermeta.id;meta.mainintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainR? Deconvolved radiuspcphys.size.radiusfloatnullablee_R? Deconvolved radius uncertaintypcstat.errorfloatnullableVcPeak Velocitykm/sphys.veloc;pos.lsrfloate_VcPeak Velocity uncertaintykm/sstat.error;pos.cartesian.yfloatsigmaVelocity dispersionkm/sphys.veloc.dispersionfloate_sigmaVelocity dispersion uncertaintykm/sstat.errorfloatTpPeak temperatureKphys.temperaturefloate_TpPeak temperature uncertaintyKstat.errorfloatICOCO(3-2) intensity100K.km.s**-1phot.fluxfloate_ICOCO(3-2) intensity uncertainty100K.km.s**-1stat.errorfloatLCOCO(3-2) luminosity100K.km.s**-1.pc**-2phys.luminosityfloate_LCOCO(3-2) luminosity uncertainty100K.km.s**-1.pc**-2stat.errorfloatMvir? Virial Mass1000solMassphys.massfloatnullablee_Mvir? Virial Mass uncertainty1000solMassstat.errorfloatnullableJ/A+A/687/A26/listList of fits filesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of regionmeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintNzNumber of slicesmeta.numberintpxPixel sizearcsecphys.angSize;instr.pixelintHPBWFinal beam widtharcsecphys.angSize;instr.beamintdVFinal spectral resolutionkm/sspect.resolutionfloatlvelLower value of velocity intervalkm/sphys.velocfloathvelHigher value of velocity intervalkm/sphys.velocfloatFileNameName of FITS file in subdirectory fitsmeta.id;meta.fitscharSizeSize of FITS fileMbytephys.size;meta.fitsint