J/ApJ/754/62ivo://CDS.VizieR/J/ApJ/754/62doi:10.26093/cds/vizier.17540062CDSAnderson L.D.Bania T.M.Balser D.S.Rood R.T.2017-09-19T14:24:05Z2014-03-31T10:35:35ZCDS support team

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

cds-question@unistra.frh-ii-regionsradio-astronomysurveysstellar-distanceUsing the H I emission/absorption method, we resolve the kinematic distance ambiguity and derive distances for 149 of 182 (82%) H II regions discovered by the Green Bank Telescope H II Region Discovery Survey (GBT HRDS). The HRDS is an X-band (9 GHz, 3 cm) GBT survey of 448 previously unknown H II regions in radio recombination line and radio continuum emission. Here, we focus on HRDS sources from 67{deg}>={ell}>=18{deg}, where kinematic distances are more reliable. The 25 HRDS sources in this zone that have negative recombination line velocities are unambiguously beyond the orbit of the Sun, up to 20kpc distant. They are the most distant H II regions yet discovered. We find that 61% of HRDS sources are located at the far distance, 31% at the tangent-point distance, and only 7% at the near distance. "Bubble" H II regions are not preferentially located at the near distance (as was assumed previously) but average 10 kpc from the Sun. The HRDS nebulae, when combined with a large sample of H II regions with previously known distances, show evidence of spiral structure in two circular arc segments of mean Galactocentric radii of 4.25 and 6.0kpc. We perform a thorough uncertainty analysis to analyze the effect of using different rotation curves, streaming motions, and a change to the solar circular rotation speed. The median distance uncertainty for our sample of H II regions is only 0.5 kpc, or 5%. This is significantly less than the median difference between the near and far kinematic distances, 6 kpc. The basic Galactic structure results are unchanged after considering these sources of uncertainty.2012ApJ...754...62Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/754/62CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/58 : A Survey of Radio H II Regions in the Northern Sky (Lockman+ 1989)VII/50 : CO Radial Velocities Toward Galactic H II Regions (Blitz+ 1982)J/MNRAS/420/1656 : RMS compact HII regions distances (Urquhart+, 2012)J/ApJ/738/27 : Galactic HII regions RRL and continuum data (Balser+, 2011)J/A+A/532/A127 : Inner Galaxy HII regions (Du+, 2011)J/ApJS/195/14 : The Bolocam Galactic Plane Survey V. (Schlingman+, 2011)J/ApJS/194/32 : The HII Region Discovery Survey (HRDS). II. (Anderson+, 2011)J/ApJ/723/492 : GRS molecular clouds physical properties (Roman-Duval+, 2010)J/ApJS/182/131 : Molecular clouds and clumps in the GRS (Rathborne+, 2009)J/ApJ/690/706 : Distances of Galactic HII regions (Anderson+, 2009)J/A+A/470/161 : UBV photometry of HII regions exciting stars (Russeil+, 2007)J/ApJ/649/759 : Bubbles in the galactic disk (Churchwell+, 2006)J/ApJ/626/195 : HI self-absorption (HISA) survey in the CGPS (Gibson+, 2005)J/ApJS/154/553 : Inner galaxy massive star formation regions (Sewilo+, 2004)J/ApJ/587/714 : H2CO and Halpha observations of UC HII (Watson+, 2003)J/ApJ/582/756 : Velocities of HII regions (Kolpak+, 2003)J/ApJS/138/63 : H2CO and Halpha observations of UC HII (Araya+, 2002)http://www.cv.nrao.edu/hrds/ : HRDS home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/754/62https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/754/62http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/754/62https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/754/62https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/754/62http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/754/62GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/754/62/table1 (HRDS (HII Region Discovery Survey) kinematic distances)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/754/62/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/754/62/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/754/62/table1?GETtext/xml+votable180.050000true276.50711-13.637390.0055555555555555565/7578 7605 7654 7679 6/12971 12974 14336 14340 14357 14365 14408 14426 29505 29507 29508 29510 29511 29522 29523 29529 29532 29533 29534 30218 30244 30245 30247 30256 30257 30258 30260 30262 30263 30269 30271 30316 30318 30319 30330 30416 30417 30419 30594 30600 30601 30604 30605 30622 30641 30644 30645 30688 30691 30694 30695 30701 30707 30710 30713 30715 32085https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/754/62?format=asciiRadiodefaultJ/ApJ/754/62/table1HRDS (HII Region Discovery Survey) kinematic distancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHRDSSource name (GLLL.lll+B.bbb)meta.id;meta.maincharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latVLSR[-76/112] Local Standard of Rest velocity from Paper II (Cat. J/ApJS/194/32)km/sphys.veloc;pos.lsrfloatVabs? Maximum velocity of detected HI absorptionkm/sspect.dopplerVelocintnullableVTPTangent point velocitykm/sphys.veloc.transversefloatDnear[0/8]? Near distancekpcpos.distance;pos.heliocentricfloatnullableDfar[3/20] Far distancekpcpos.distance;pos.heliocentricfloatN/F[FNT] Kinematic distance ambiguity resolution (F:Far, N:Near or T:Tangent)meta.codecharQF[A-C] Quality Factor (A: most confident KDA determination) (1)meta.code.qualcharDist[3.4/19.7]? Derived heliocentric distancekpcpos.distancefloatnullablee_Dist[0/1.6]? Uncertainty in Distkpcstat.errorfloatnullableRGal[3/15] Galactocentric radiuskpcpos.distance;pos.galactocentricfloatZdist[-150/250]? Distance from Galactic planepcpos.cartesian.z;pos.galacticintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexed