J/A+A/600/A2ivo://CDS.VizieR/J/A+A/600/A2doi:10.26093/cds/vizier.36000002CDSWinkel B.Wiesemeyer H.Menten K.M.Sato M.Brunthaler A.,Wyrowski F.Neufeld D.Gerin M.Indriolo N.2017-12-12T14:44:45Z2017-03-17T07:40:58ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyh-i-line-emissioninterstellar-mediumspectroscopyRecent sub-millimeter and far-infrared wavelength observations of absorption in the rotational ground state lines of various simple molecules against distant Galactic continuum sources have opened the possibility to study the chemistry of diffuse molecular clouds Milky Way-wide. In order to calculate abundances the column densities of molecular and atomic hydrogen, HI, must be known. We aim at determining the atomic hydrogen column densities for diffuse clouds located on the sight lines toward a sample of prominent high mass star forming regions that were intensely studied with the HIFI instrument onboard Herschel. Based on Jansky Very Large Array data, we employ the 21-cm HI absorption-line technique to construct profiles of the HI opacity versus radial velocity toward our target sources. These profiles are combined with lower resolution archival data of extended HI emission to calculate the HI column densities of the individual clouds along the sight lines. We employ Bayesian inference to estimate the uncertainties of the derived quantities. Our study delivers reliable estimates of the atomic hydrogen column density for a large number of diffuse molecular clouds at various Galactocentric distances. Together with column densities of molecular hydrogen derived from its surrogates observed with HIFI, the measurements can be used to characterize the clouds and, e.g., investigate the dependence of their chemistry on the molecular fraction.2017A&A...600A...2Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/600/A2CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/542/A110 : Neutral gas in the Milky Way halo (Ben Bekhti+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/600/A2https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/600/A2http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/600/A2https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/600/A2https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/600/A2http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/600/A2GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/600/A2/sources (List of observed sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/600/A2/sources?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/600/A2/sources?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/600/A2/sources?GETtext/xml+votable180.050000true266.835-28.3855560.005555555555555556Cone search capability for table J/A+A/600/A2/sightlin (List of analyzed sight lines)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/600/A2/sightlin?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/600/A2/sightlin?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/600/A2/sightlin?GETtext/xml+votable180.050000true266.839167-28.4191670.0055555555555555566/14704 28830 29091 29101 30269 30318 30618 30694https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/600/A2?format=asciiRadioOpticaldefaultJ/A+A/600/A2/sourcesList of observed sourcesSimbadNameSimbad column added by the CDSmeta.idcharSLnumNumber of extracted sight linesmeta.numberintNameSource namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000.0) of phase centerpos.eq.ra;meta.mainDEJ2000Declination (J2000.0) of phase centerpos.eq.dec;meta.mainGLONGalactic longitude of phase centerdegpos.galactic.lonGLATGalactic latitude of phase centerdegpos.galactic.latfloatFileNameAssociated FITS file in subdirectory fitsmeta.id.assoc;meta.fitscharJ/A+A/600/A2/sightlinList of analyzed sight linesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.maincharIDSight line IDmeta.id;spect.linecharRAJ2000Right ascension (J2000.0) of sight linepos.eq.ra;meta.mainDEJ2000Declination (J2000.0) of sight linepos.eq.dec;meta.mainGLONGalactic longitude of sight linedegpos.galactic.lonGLATGalactic latitude of sight linedegpos.galactic.latfloatFileNameAssociated FITS file in subdirectory fitsmeta.id.assoc;meta.fitschar