J/PASJ/72/43ivo://CDS.VizieR/J/PASJ/72/43doi:10.26093/cds/vizier/bj-28-1bCDSNakanishi H.Fujita S.Tachihara K.et AL.2026-03-17T20:05:49Z2021-05-05T07:44:41ZCDS support team

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

cds-question@unistra.frgalaxy-planesmilky-way-galaxymolecular-cloudsh-i-line-emissiongalaxy-kinematicsWe analyze molecular-gas formation in neutral atomic hydrogen (HI) clouds using the latest CO data, obtained from the FOREST (four-beam receiver system on the 45m telescope) unbiased Galactic plane imaging survey with the Nobeyama 45m telescope, and using HI data taken from the Very Large Array Galactic plane survey. We applied a dendrogram algorithm to the HI data cube to identify HI clouds, and we calculated the HI mass and molecular-gas mass by summing the CO line intensity within each HI cloud. On the basis of the results, we created a catalog of 5737 identified HI clouds with local standard of rest (LSR) velocity of VLSR<=-20km/s in galactic longitude and latitude ranges of 20{deg}<=l<=50{deg} and -1{deg}<=b<=1{deg}, respectively. We found that most of the HI clouds are distributed within a Galactocentric distance of 16kpc, and most of them are in the cold neutral medium phase. In addition, we determined that the high-mass end of the HI mass function is fitted well with a power-law function with an index of 2.3. Although two sequences of self-gravitating and diffuse clouds are expected to appear in the M_tot_-M_H2_ diagram according to previous works based on a plane-parallel model, the observational data show only a single sequence with large scattering within these two sequences. This implies that most of the clouds are mixtures of these two types of clouds. Moreover, we suggest the following scenario of molecular-gas formation: an HI-dominant cloud evolved with increasing H2 mass along a path of M_H2_{prop.to}M^2^_tot_ by collecting diffuse gas before reaching and moving along the curves of the two sequences.2020PASJ...72...43Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/PASJ/72/43CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/122/3155 : Peculiar HI cloud near galactic plane (Higgs+, 2001)J/ApJ/626/887 : HI clouds in Southern Galactic Plane Survey (Kavars+, 2005)J/ApJ/722/367 : HI clouds in Quadrant I of the Milky Way (Ford+, 2010)J/ApJ/770/L4 : HI clouds around the Galactic Center (McClure-Griffiths+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/PASJ/72/43https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/PASJ/72/43http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/PASJ/72/43https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/PASJ/72/43https://vizier.iucaa.in/viz-bin/votable?-source=J/PASJ/72/43http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/PASJ/72/43GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/PASJ/72/43/table1 (Identified HI clouds)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/PASJ/72/43/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/PASJ/72/43/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/PASJ/72/43/table1?GETtext/xml+votable180.050000true288.63959.93690.0055555555555555565/7382-7383 7554 7561 7564 7567 7578-7579 7604-7605 7648 7651 7654 7661 7672-7673 6/29509 29511 29517 29520 29522-29523 29526-29527 29557 30222-30223 30234 30240-30241 30243 30260 30262-30265 30306-30307 30328 30330-30331 30334 30401 30404-30405 30428-30429 30598-30601 30603 30610 30620 30622-30623 30629 30640-30641 30666-30667 30697 30700-30701https://cdsarc.cds.unistra.fr/viz-bin/moc/J/PASJ/72/43?format=asciiRadiodefaultJ/PASJ/72/43/table1Identified HI cloudsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[1/5737] Sequential numbermeta.id;meta.mainintGLONGalactic longitudedegpos.galactic.lonGLATGalactic longitudedegpos.galactic.latVLSRLSR velocitykm/sphys.veloc;pos.lsrfloatDHeliocentric distancekpcpos.distance;pos.heliocentricfloatRGalactocentric distancekpcpos.distance;pos.galactocentricfloatRminMinor-axis radiuspcphys.angSize;srcfloatRmajMajor-axis radiuspcphys.angSizefloatPA[] Position angledegpos.posAngfloatsigmaVelocity dispersionkm/sphys.veloc.dispersionfloatMHIHI masssolMassphys.massfloate_MHIrms uncertainty on MHIsolMassstat.errorfloatMH2H_2_ masssolMassphys.massfloate_MH2rms uncertainty on MH2solMassstat.errorfloat_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