J/ApJ/587/714ivo://CDS.VizieR/J/ApJ/587/714doi:10.26093/cds/vizier.15870714CDSWatson C.Araya E.Sewilo M.Churchwell E.Hofner P.Kurtz S.2017-10-09T13:33:54Z2014-02-23T17:02:45ZCDS support team

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

cds-question@unistra.frh-ii-regionsradio-astronomyFifty-four ultracompact (UC) HII regions in the GLIMPSE survey region (|b|<1{deg} and 30{deg}<l<70{deg}) were observed in H_2_CO and H110{alpha} using the 305 m Arecibo telescope. By analyzing H_2_CO absorption against the UC H II region continuum emission, we resolve the distance ambiguity toward 44 sources. This determination is critical to measure global physical properties of UC H II regions (e.g., luminosity, size, mass) and properties of the Galaxy (e.g., spiral structure, abundance gradients). We find that the distribution of UC H II regions in this survey is consistent with a ``local spur'', the Perseus, Sagittarius, and Scutum arms as delineated by Taylor & Cordes. However, departures from model velocities produce distance uncertainties only slightly smaller than the proposed arm separations.2003ApJ...587..714Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/587/714CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)J/A+AS/115/81 : A CS(2-1) survey of UC HII regions (Bronfman+, 1996)J/A+AS/120/283 : Water maser features in UC HII regions (Hofner+ 1996)J/A+A/336/339 : VLA observations of ultracompact HII regions (Molinari+ 1998)J/MNRAS/301/640 : Ultracompact H II regions studies. II. (Walsh+, 1998)J/ApJS/138/63 : H2CO and Halpha observations of UC HII (Araya+, 2002)J/ApJS/155/123 : JHKs photometry of ultracompact HII regions (Alvarez+, 2004)J/A+A/417/615 : Maser and outflows in UC HII region (Codella+, 2004)J/A+A/453/1003 : SCUBA ultracompact HII regions (Thompson+, 2006)J/ApJS/91/659 : Ultracompact HII regions radio images (Kurtz+ 1994)J/MNRAS/420/1656 : RMS compact HII regions distances (Urquhart+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/587/714https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/587/714http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/587/714https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/587/714https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/587/714http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/587/714GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/587/714/table1 (Observed sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/587/714/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/587/714/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/587/714/table1?GETtext/xml+votable180.050000true282.402903-0.6847790.0055555555555555566/12975 14353 14354 14355 14403 14409 14594 30312 30313 30318 30319 30330 30405 30416 30417 30420 30423 30594 30595 30600 30605 30616 30618 30622 30623 30644 30691 30694 30695 30701 30714 30715 30716 307191.6558465556080236e-21 2.241051079335579e-21https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/587/714?format=asciiRadiodefaultJ/ApJ/587/714/table1Observed sourcesIRASIRAS namemeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name, GLL.ll+D.ddmeta.id;meta.maincharprimaryRAB1950Right ascension (B1950)pos.eq.ra;meta.mainDEB1950Declination (B1950)pos.eq.dec;meta.mainS100IRAS 100{mu}m flux densityhJyphot.flux.density;em.IR.60-100umfloatSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)pos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)pos.eq.decnullableindexedJ/ApJ/587/714/table3Formaldehyde (H_2_CO, 4829.66MHz) line parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name (1)meta.id;meta.maincharCNameIntervening cloud identification (1)meta.idcharSc? Continuum flux densitymJyphot.flux.densitydoublenullablee_Sc? The 1{sigma} error in ScmJystat.errorfloatnullableSH2CO? H_2_CO flux densitymJyphot.fluxfloatnullablee_SH2CO? The 1{sigma} error in SH2COmJystat.errorfloatnullableVLSR? The Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloatnullablel_VLSRLimit flag on the VLSR errormeta.code.error;phys.veloc;pos.lsrchare_VLSR? The 1{sigma} error in VLSRkm/sstat.error;phys.veloc;pos.lsrfloatnullableFWHM? The Full-Width at Half-Maximumkm/sspect.line.widthfloatnullablel_FWHMLimit flag on the FWHM errormeta.code.error;phys.angSizechare_FWHM? The 1{sigma} error in FWHMkm/sstat.error;phys.angSizefloatnullableSint? The integrated H_2_CO line fluxmJy.km/sphot.flux.density;spect.lineintnullablel_SintLimit flag on the Sint errormeta.code.errorchare_Sint? The 1{sigma} error on SintmJy.km/sstat.errorintnullableJ/ApJ/587/714/table4Kinematic parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.maincharf_Name[a] Note on near/far distance (1)meta.codecharCNameIntervening cloud identificationmeta.idcharVLSRThe Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloate_VLSRThe 1{sigma} error in VLSRkm/sstat.error;phys.veloc;pos.lsrfloatDNear? Inner Galaxy circular orbit near distancekpcpos.distancefloatnullableDFar? Inner Galaxy circular orbit far distancekpcpos.distancefloatnullableVTPDistance derived to tangent pointkpcpos.distancefloatDTPResolved Distancekpcpos.distancefloatDLSR? Distance derived from VLSRkpcpos.distancefloatnullableE_DLSR? Upper 1{sigma} error in DLSRkpcstat.error;stat.maxfloatnullablee_DLSR? Lower 1{sigma} error in DLSRkpcstat.errorfloatnullablez? Galactic scale heightpcinstr.scale;pos.galacticintnullableDGCDistance from the Galactic centerkpcpos.distance;pos.galactocentricfloatNear/FarComment on the source distance (2)meta.notecharJ/ApJ/587/714/table2H110{alpha} line (4874.16MHz) and continuum parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.maincharf_Name[a] SNR (1)meta.codecharScContinuum flux densitymJyphot.flux.densityfloate_ScThe 1{sigma} error in ScmJystat.errorfloatSH110a? H110{alpha} flux densitymJyphot.flux;em.line.Halphafloatnullablee_SH110a? The 1{sigma} error in SH110amJystat.errorfloatnullableVLSR? The Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR? The 1{sigma} error in VLSRkm/sstat.error;phys.veloc;pos.lsrfloatnullableFWHM? The Full-Width at Half-Maximumkm/sspect.line.widthfloatnullablee_FWHM? The 1{sigma} error in FWHMkm/sstat.error;phys.angSizefloatnullableSint? The integrated H110{alpha} line fluxmJy.km/sphot.flux.density;spect.lineintnullablel_SintLimit flag on Sint error (e_Sint)meta.code.errorchare_Sint? The 1{sigma} error on SintmJy.km/sstat.errorintnullable