J/ApJ/686/384ivo://CDS.VizieR/J/ApJ/686/384doi:10.26093/cds/vizier.16860384CDSDu F.Yang J.2018-01-30T07:18:08Z2011-01-10T12:57:55ZCDS support team

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

cds-question@unistra.frmolecular-cloudsinterstellar-mediuminfrared-sourcesradio-astronomyInfrared dark clouds (IRDCs) are extinction features against the Galactic infrared background, mainly in the mid-infrared band. Recently they were proposed to be potential sites of massive star formation. In this work we have made a ^12^CO, ^13^CO, and C^18^O (J=1->0) survey of 61 IRDCs, 52 of which are in the first Galactic quadrant, selected from a catalog given by Simon and coworkers (2006, Cat. J/ApJ/639/227), while the others are in the outer Galaxy, selected by visually inspecting the Midcourse Space Experiment (MSX) images. Detection rates in the three CO lines are 90%, 71%, and 62%, respectively. The distribution of IRDCs in the first Galactic quadrant is consistent with the 5kpc molecular ring picture, while a slight trace of a spiral pattern is also noticeable, and needs to be further examined. The IRDCs have a typical excitation temperature of 10K and typical column density of several 10^22^cm^-2^. Their typical physical size is estimated to be several parsecs using angular sizes from the Simon catalog.2008ApJ...686..384Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/686/384CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/639/227 : MSX IRDC candidate catalog (Simon+, 2006)J/ApJ/653/1325 : Galactic distribution of infrared dark clouds (Simon+, 2006)J/ApJS/166/567 : Radio Molecular lines in infrared dark clouds (Ragan+, 2006)J/ApJ/641/389 : Millimetric observations of IRDC cores (Rathborne+, 2006)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/686/384https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/686/384http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/686/384https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/686/384https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/686/384http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/686/384GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/686/384/irdc (Physical parameters (table 4) and coordinates (table 1) of the IRDCs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/686/384/irdc?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/686/384/irdc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/686/384/irdc?GETtext/xml+votable180.050000true270.52083-21.597780.0055555555555555566/3648 14308 14621 14647 14652 14653 14661 14665 14689 14697 14698 14699 14701 14706 14741 15362 15456 22249 23982 24554 28917 28918 29094 29097 29103 29112 29113 29114 29118 29459 29504 29510 29511 29512 29529 29533 30216 30218 30256 30258 30312 30316 30319 30341 30417 30421 30429 30695https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/686/384?format=asciiInfraredRadiodefaultJ/ApJ/686/384/irdcPhysical parameters (table 4) and coordinates (table 1) of the IRDCsSize? Size (4)pcphys.size.diameterfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqRunning sequence numbermeta.id;meta.mainintprimaryMSXDCSource name (GLLL.ll+BB.bb)meta.id;meta.maincharn_MSXDC[ab] Adopted peak: first (a) or second (b)meta.notecharGLONGalactic longitude coordinatedegpos.galactic.lonGLATGalactic latitude coordinatedegpos.galactic.latfloatRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainTexc? Excitation temperature (2)Kphys.atmol.excitationfloatnullableDist? Heliocentric distance (3)kpcpos.distancefloatnullabletau13? ^13^CO optical depthphys.absorption.opticalDepthfloatnullableNH2.13? H_2_ column density with ^13^CO (5)1e+22cm**-2phys.columnDensityfloatnullablenH2.13? H_2_ volume density with ^13^CO (5)cm**-3phys.densityintnullableM13? Mass with ^13^CO (5)solMassphys.massintnullabletau18? C^18^O optical depthphys.absorption.opticalDepthfloatnullableNH218? H_2_ column density with C^18^O (5)1e+22cm**-2phys.columnDensityfloatnullablenH2.18? H_2_ volume density with C^18^O (5)cm**-3phys.densityintnullableM18? Mass with C^18^O (5)solMassphys.massintnullableS06Display the corresponding MSX IRDC dark cloud candidates from Simon et al., 2006, Cat. J/ApJ/639/227meta.ref.urlcharJ/ApJ/686/384/table3Observed properties of the IRDCsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqRunning sequence numbermeta.id;meta.mainintm_SeqMultiple component of the same source (1)meta.code.multipcharMSXDCName (GLLL.ll+BB.bb)meta.id;meta.maincharTR12? ^12^CO radiation temperature T^*^_R_Kphot.antennaTempfloatnullablee_TR12? TR12 uncertaintyKstat.errorfloatnullableInt12? ^12^CO integrated intensityK.km/sphot.flux.density;em.line.COfloatnullableVlsr12? ^12^CO local standard of rest (LSR) velocitykm/sstat.errorfloatnullabledV12? ^12^CO line widthkm/sspect.line.widthfloatnullableTR13? ^13^CO radiation temperature T^*^_R_Kphot.antennaTempfloatnullablee_TR13? TR13 uncertaintyKstat.errorfloatnullableInt13? ^13^CO integrated intensityK.km/sphot.flux.density;em.line.COfloatnullableVlsr13? ^13^CO local standard of rest (LSR) velocitykm/sstat.errorfloatnullabledV13? ^13^CO line widthkm/sspect.line.widthfloatnullableTR18? C^18^O radiation temperature T^*^_R_Kphot.antennaTempfloatnullablee_TR18? TR18 uncertaintyKstat.errorfloatnullableInt18? C^18^O integrated intensityK.km/sphot.flux.density;em.radiofloatnullableVlsr18? C^18^O local standard of rest (LSR) velocitykm/sphys.veloc;pos.lsrfloatnullabledV18? C^18^O line widthkm/sspect.line.widthfloatnullable