J/ApJ/926/186ivo://CDS.VizieR/J/ApJ/926/186doi:10.26093/cds/vizier/ba-wy-5tCDSDickey J.M.Dempsey J.M.Pingel N.M.McClure-Griffiths N.M.,Jameson K.Dawson J.R.Denes H.Clark S.E.Joncas G.Leahy D.,Lee M.-Y.Miville-Deschenes M.-A.Stanimirovic S.Tremblay C.D.,van Loon J.T.2026-07-02T11:58:25Z2023-12-04T11:38:56ZCDS support team

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

cds-question@unistra.frinterstellar-mediumradio-astronomymilky-way-galaxyUsing the Australian Square Kilometre Array Pathfinder to measure 21cm absorption spectra toward continuum background sources, we study the cool phase of the neutral atomic gas in the far outer disk, and in the inner Galaxy near the end of the Galactic bar at longitude 340{deg}. In the inner Galaxy, the cool atomic gas has a smaller scale height than in the solar neighborhood, similar to the molecular gas and the super-thin stellar population in the bar. In the outer Galaxy, the cool atomic gas is mixed with the warm, neutral medium, with the cool fraction staying roughly constant with the Galactic radius. The ratio of the emission brightness temperature to the absorption, i.e., 1-e^-{tau}^, is roughly constant for velocities corresponding to Galactic radius greater than about twice the solar circle radius. The ratio has a value of about 300K, but this does not correspond to a physical temperature in the gas. If the gas causing the absorption has kinetic temperature of about 100K, as in the solar neighborhood, then the value 300 K indicates that the fraction of the gas mass in this phase is one-third of the total HI mass.2022ApJ...926..186Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/926/186CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/psr : ATNF Pulsar Catalogue (Manchester+, 2005)VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)VII/284 : A Catalogue of Galactic Supernova Remnants (Green, 2019)J/A+AS/76/317 : Possible new PNe in IRAS PSC (Preite-Martinez, 1988)J/A+A/275/67 : Velocity Field of the outer Galaxy (Brand+ 1993)J/ApJ/649/759 : Bubbles in the galactic disk (Churchwell+, 2006)J/ApJ/783/130 : Parallaxes of high mass star forming regions (Reid+, 2014)J/ApJ/793/132 : Perseus cloud sources Gaussian param. (Stanimirovic+, 2014)J/A+A/568/A41 : ATLASGAL Compact Source Catalog: 280<l<60 (Urquhart+, 2014)J/ApJS/212/1 : The WISE catalog of Galactic HII regions (Anderson+, 2014)J/ApJS/221/26 : Radio obs. of Galactic WISE HII regions (Anderson+, 2015)J/A+A/594/A116 : HI4PI spectra and column density maps (HI4PI team+, 2016)J/ApJ/831/124 : Milky Way kinematics. II. (McClure-Griffiths+, 2016)J/ApJ/834/57 : MW molecular clouds from ^12^CO (Miville-Deschenes+, 2017)J/ApJS/238/14 : 21-SPONGE HI Absorption Line Survey. I. (Murray+, 2018)J/ApJ/856/52 : Kinematic distances of star-forming regions (Wenger+, 2018)J/ApJS/244/7 : ATCA HI abs. survey in Magellanic clouds. I. (Jameson+, 2019)J/ApJ/880/141 : Arecibo 21cm obs. of sources in 5 GMC regions (Nguyen+, 2019)J/ApJ/885/131 : ~200 high-mass SFR plx & proper motion with VLBI (Reid+, 2019)J/ApJ/887/114 : VLA ~8-10GHz obs. of WISE Galactic HII regions (Wenger+, 2019)J/ApJ/899/15 : Parameters for the 58 {tau}HI(v) sightlines (Murray+, 2020)J/ApJ/910/131 : Molecular gas distribution from MWISP CO survey (Su+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/926/186https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/926/186http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/926/186https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/926/186https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/926/186http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/926/186GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/926/186/table4 (Galactic sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/926/186/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/926/186/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/926/186/table4?GETtext/xml+votable180.050000true247.6075-46.04750.005555555555555556Cone search capability for table J/ApJ/926/186/table5 (Extragalactic sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/926/186/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/926/186/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/926/186/table5?GETtext/xml+votable180.050000true247.310417-45.6880560.0055555555555555565/10551 10556-10557 10594-10595 10600 6/42199 42201-42203 42213-42215 42221 42232-42233 42235-42238 42369-42372 42374-42375 42386-42387 42392 42394 42404 42408https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/926/186?format=asciiRadiodefaultJ/ApJ/926/186/table4Galactic sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[3/331] Index numbermeta.id;meta.mainintRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainGLON[336.36/344.23] Galactic longitudedegpos.galactic.lonGLAT[-3.12/1.62] Galactic latitudedegpos.galactic.latfloatTau[0.004/0.81] Optical depth noise,{sigma}_{tau}_stat.snr;phys.absorption.opticalDepthfloatOTypeObject type identification (1)meta.id;src.classcharStrctStructure (2)src.classcharA14Display data from Anderson+ 2014, J/ApJS/212/1 within 36"meta.ref.urlintnullableD22Display data from Dickey+ 2022, J/A+A/568/A41 within 36"meta.ref.urlintnullableJ/ApJ/926/186/table5Extragalactic sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[0/346] Index numbermeta.id;meta.mainintRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainGLON[336.6/344] Galactic longitudedegpos.galactic.lonGLAT[-3.4/3.4] Galactic latitudedegpos.galactic.latfloatTau[0.01/0.5] Optical depth noise, {sigma}_{tau}_stat.snr;phys.absorption.opticalDepthfloatStrctStructure (1)src.classchar