J/ApJS/138/63ivo://CDS.VizieR/J/ApJS/138/63doi:10.26093/cds/vizier.21380063CDSAraya E.Hofner P.Churchwell E.Kurtz S.2017-06-21T08:22:28Z2014-02-23T17:07:59ZCDS support team

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

cds-question@unistra.frh-ii-regionsradio-astronomyWe report observations of the H110{alpha} radio recombination line and H_2_CO (1_10_-1_11_) toward 21 ultracompact H II regions with the Arecibo 305m radio telescope. We detect the H110{alpha} line in 20 sources, and for each of these we also detect a H_2_CO absorption feature at nearly the same velocity, demonstrating the association between molecular and ionized gas. We determine kinematic distances and resolve the distance ambiguity for all observed HII regions, as well as for 19 intervening molecular clouds. A plot of the Galactic distribution of these objects traces part of the spiral structure in the first Galactic quadrant. We compare flux densities and velocities as measured with the Arecibo Telescope with interferometric measurements of our sample of ultracompact HII regions. In general, the single-dish fluxes exceed the interferometric values, consistent with an extended component of radio continuum emission.2002ApJS..138...63Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/138/63CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/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/ApJ/587/714 : H2CO and Halpha observations of UC HII (Watson+, 2003)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/ApJS/138/63https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/138/63http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/138/63https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/138/63https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/138/63http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/138/63GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/138/63/sources (Observed H110{alpha} lines)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/138/63/sources?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/138/63/sources?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/138/63/sources?GETtext/xml+votable180.050000true282.628561-0.0334220.0055555555555555566/14358 14359 14594 14624 30312 30313 30318 30319 30328 30405 30420 30604 30617 30622 30644 30691 30701https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/138/63?format=asciiRadiodefaultJ/ApJS/138/63/sourcesObserved H110{alpha} linesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameHII region designation, GLL.ll+D.ddmeta.id;meta.maincharprimaryRAB1950Right ascension (B1950)pos.eq.ra;meta.mainDEB1950Declination (B1950)pos.eq.dec;meta.mainRef1[1/9] Reference for UC HII region flux density (2)meta.ref;pos.frameintRef2[1/9]? Reference for UC HII region velocity (2)meta.ref;pos.frameintnullableRef3[1/9]? Reference for previously determined distance (2)meta.ref;pos.frameintnullableONameOther name of the region (1)meta.idcharSc? Continum emission flux densityJyphot.flux.densityfloatnullablee_Sc? 1{sigma} error on ScJystat.errorfloatnullablen_Sc[a] a: Continum emission in off positionmeta.notecharSH110a? Continum emission in off positionJyphot.flux.densityfloatnullablee_SH110a? 1{sigma} error on SH110a (1)Jystat.errorfloatnullablen_SH110a[b] b: No detection of H110{alpha} linemeta.notecharVLSR? Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR? 1{sigma} error on VLSR (1)km/sstat.error;phys.veloc;pos.lsrfloatnullableFWHM? Full-Width at Half-Maximumkm/sspect.line.widthfloatnullablee_FWHM? 1{sigma} error on FWHM (1)km/sstat.error;phys.angSizefloatnullableSint? Integrated H110{alpha} line fluxJy.km/sphot.flux.density;spect.linefloatnullablee_Sint? 1{sigma} error on Sint (1)Jy.km/sstat.errorfloatnullableRS? Flux density ratio HII to UCHIIphot.flux;arith.ratiofloatnullable_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/ApJS/138/63/table5Kinematic parametersDGCDistance from the Galactic centerkpcpos.distance;pos.galactocentricfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.maincharn_Name[a] a: kinematic locationmeta.notecharCNameIntervening cloud identificationmeta.idcharm_CName[ac] Multiplicty index on CNamemeta.code.multipcharVLSRThe Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloatn_VLSR[i] Note on VLSR (1)meta.notecharDNear? 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.distancefloatnullableu_DLSR[?] Uncertainty flag on DLSRmeta.code.errorcharNear/FarSource distance (Near, Far, Tangent)meta.notecharn_Near/Far[bcdefhj] Note on Near/Far (1)meta.notecharJ/ApJS/138/63/table4Formaldehyde (H_2_CO, 4829.66MHz) resultsNoteNotes (1)meta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameHII region designationmeta.id;meta.maincharm_Name[abc] Multiplicity index on Namemeta.code.multipcharCNameIntervening cloud identificationmeta.idcharm_CName[abcd] Multiplicity index on CNamemeta.code.multipcharSH2CO? H_2_CO flux densityJyphot.fluxfloatnullablee_SH2CO? rms uncertainty on SH2COJystat.errorfloatnullableVLSR? Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR? 1{sigma} error on VLSRkm/sstat.error;phys.veloc;pos.lsrfloatnullablen_VLSR[b] b: No detectionmeta.notecharFWHM? Line widthkm/sspect.line.widthfloatnullablee_FWHM? 1{sigma} error on Widthkm/sstat.error;phys.angSizefloatnullableSint? Integrated H110{alpha} line fluxJy.km/sphot.flux.density;spect.linefloatnullablee_Sint? 1{sigma} error on SintJy.km/sstat.errorfloatnullablef_Note[abc] Additional remarks (2)meta.notechar