J/ApJ/798/L27ivo://CDS.VizieR/J/ApJ/798/L27doi:10.26093/cds/vizier.17989027CDSSun Y.Xu Y.Yang J.Li F.-C.Du X.-Y.Zhang S.-B.Zhou X.2017-10-16T10:43:02Z2015-06-30T08:14:22ZCDS support team

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

cds-question@unistra.frmolecular-cloudsmilky-way-galaxyradio-astronomyCombining H I data from the Canadian Galactic Plane Survey and CO data from the Milky Way Imaging Scroll Painting project (MWISP), we have identified a new segment of a spiral arm between Galactocentric radii of 15 and 19kpc that apparently lies beyond the Outer Arm in the second Galactic quadrant. Over most of its length, the arm is 400-600pc thick in z. The new arm appears to be the extension of the distant arm recently discovered by Dame & Thaddeus (2011ApJ...734L..24D) as well as the Scutum-Centaurus Arm into the outer second quadrant. Our current survey identified a total of 72 molecular clouds with masses on the order of 10^2^-10^4^M_{sun}_ that probably lie in the new arm. When all of the available data from the CO molecular clouds are fit, the best-fitting spiral model gives a pitch angle of 9.3{deg}+/-0.7{deg}.2015ApJ...798L..27Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/798/L27CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)VI/128 : Log of CGPS exposures (Taylor+, 2003-)J/ApJS/196/18 : CO survey of galactic molecular clouds. II. (Bieging+, 2011)J/A+A/470/161 : UBV photometry of HII regions exciting stars (Russeil+, 2007)J/A+A/399/1083 : Outer Galaxy IRAS sources and 12CO emission (Kerton+, 2003)J/ApJS/144/47 : Outer galaxy molecular cloud catalog (Brunt+, 2003)J/A+A/397/133 : Star-forming complexes in the Galaxy (Russeil+, 2003)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/798/L27https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/798/L27http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/798/L27https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/798/L27https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/798/L27http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/798/L27GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/798/L27/table1 (Parameters of molecular clouds derived by CO(1-0))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/798/L27/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/798/L27/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/798/L27/table1?GETtext/xml+votable180.050000true329.5387758.65490.0055555555555555566/3066 3071 3160 3163 3187 3188 3192 3194 3196 3269 3271 3273 3275 3280 3296 3297 3303 3605 3607 3644 3646 3648 3656 3658 3680 3688 3723 3724 3726 3727 3731 3736 3737 3745 3747 3748 14323 14324 14335 15627 15630 15631 15639 15642 15645 15653 15665 15680 15682 15683 15689https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/798/L27?format=asciiRadiodefaultJ/ApJ/798/L27/table1Parameters of molecular clouds derived by CO(1-0)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/72] Running sequence numbermeta.id;meta.mainintr_SeqDetections of the source (1)meta.ref;pos.framecharGLONGalactic longitude of the CO emission peakdegpos.galactic.lonGLATGalactic latitude of the CO emission peakdegpos.galactic.latVlsr[-121/-74] LSR velocity of the CO linekm/sspect.dopplerVelocfloatTpk[1.3/8] CO peak temperatureKphot.antennaTempfloatdV[0.7/3.3] The CO line width {Delta}Vkm/sspect.line.widthfloatWCO[1.6/18] CO integrated intensityK.km/sphot.flux.density;em.line.COfloatArea[3/114] Angular area of the complex defined by the 3{sigma} limitarcmin**2phys.angAreafloatDist[9/15] Heliocentric distance (d) (2)kpcpos.distancefloatR[14/22] Galactocentric distance (R) (2)kpcpos.distance;pos.galactocentricfloatZsc[-0.4/0.8] Scale height (z=Dsin(b))kpcpos.cartesian.z;pos.galacticfloatRad[2.6/19.5] Cloud radius (3)pcphys.size.radiusfloatMass[0.2/60.5] Cloud mass (4)ksolMassphys.massfloatB03Display data from Brunt+, 2003, J/ApJS/144/47meta.ref.urlcharSimbadSimbad 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