J/ApJ/819/143ivo://CDS.VizieR/J/ApJ/819/143doi:10.26093/cds/vizier.18190143CDSCampbell J.L.Friesen R.K.Martin P.G.Caselli P.Kauffmann J.,Pineda J.E.2018-10-18T15:22:13Z2016-06-22T09:04:32ZCDS support team

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

cds-question@unistra.frradio-astronomymolecular-cloudsgalaxy-kinematicsinterstellar-mediumWe report the results of an HCO^+^ (3-2) and N_2_D^+^ (3-2) molecular line survey performed toward 91 dense cores in the Perseus molecular cloud using the James Clerk Maxwell Telescope, to identify the fraction of starless and protostellar cores with systematic radial motions. We quantify the HCO^+^ asymmetry using a dimensionless asymmetry parameter {delta}_v_, and identify 20 cores with significant blue or red line asymmetries in optically thick emission indicative of collapsing or expanding motions, respectively. We separately fit the HCO^+^ profiles with an analytic collapse model and determine contraction (expansion) speeds toward 22 cores. Comparing the {delta}_v_ and collapse model results, we find that {delta}_v_ is a good tracer of core contraction if the optically thin emission is aligned with the model-derived systemic velocity. The contraction speeds range from subsonic (0.03km/s) to supersonic (0.40km/s), where the supersonic contraction speeds may trace global rather than local core contraction. Most cores have contraction speeds significantly less than their free-fall speeds. Only 7 of 28 starless cores have spectra well-fit by the collapse model, which more than doubles (15 of 28) for protostellar cores. Starless cores with masses greater than the Jeans mass (M/M_J_>1) are somewhat more likely to show contraction motions. We find no trend of optically thin non-thermal line width with M/M_J_, suggesting that any undetected contraction motions are small and subsonic. Most starless cores in Perseus are either not in a state of collapse or expansion, or are in a very early stage of collapse.2016ApJ...819..143Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/819/143CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/220/11 : SEDs of Spitzer YSOs in the Gould Belt (Dunham+, 2015)J/ApJ/786/29 : Catalog of distances to molecular clouds (Schlafly+, 2014)J/MNRAS/402/603 : SCUBA cores in Perseus mol. cloud (Curtis+, 2010)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/ApJ/696/298 : Dense cores in Perseus (Foster+, 2009)J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)J/ApJS/175/509 : Ammonia spectral atlas in Perseus (Rosolowsky+, 2008)J/A+A/472/187 : submm cores in Perseus (Hatchell+, 2007)J/ApJ/668/1042 : Dense cores in Perseus molecular cloud (Kirk+, 2007)J/ApJ/646/1009 : Structures of dust in Perseus molecular cloud (Kirk+, 2006)J/ApJ/638/293 : 1.1mm sources in the Perseus Molecular Cloud (Enoch+, 2006)J/ApJS/125/161 : A database of dense cores mapped in ammonia (Jijina+, 1999)J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/819/143https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/819/143http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/819/143https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/819/143https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/819/143http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/819/143GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/819/143/table1 (Summary of observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/819/143/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/819/143/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/819/143/table1?GETtext/xml+votable180.050000true51.2512530.736250.0055555555555555566/857 858 859 860 861 862 880 881 1538 1539 1542 1544https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/819/143?format=asciiRadiodefaultJ/ApJ/819/143/table1Summary of observationsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMdisplay more data in table 2 and/or 4meta.ref.urlcharNameSource designation (1)meta.id;meta.maincharprimaryf_Name[ ,b-f] Flag(s) on Name (2)meta.codecharBolo[1/121]? Bolo number (<[EYG2006] Bolo NNN> in Simbad)meta.id.crossintnullableRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainTpk1[0.4/10.7]? HCO^+^ peak temperatureKphys.temperaturefloatnullablerms1[0.08/1.3] HCO^+^ rmsKstat.stdev;instr.det.noisefloatTpk2[0.4/2.1]? N_2_D^+^ peak temperaturephys.temperaturefloatnullablef_Tpk2[f] Flag on Tpk2 (2)meta.codecharrms2[0.07/0.4]? N_2_D^+^ rmsstat.stdev;instr.det.noisefloatnullableProtoProtestellar? (Y or N)meta.codecharRefID reference (3)pos.framecharJ/ApJ/819/143/table2*Summary of Perseus dense core kinematicsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource designationmeta.id;meta.maincharf_NameFlag on Name (1)meta.codecharVthin[3.5/10.3] N_2_D+/N_2_H+/NH_3_ systemic velocitykm/sphys.veloc;pos.heliocentricfloate_Vthin[0/0.1] Vthin uncertaintykm/sstat.errorfloatSthin[0.1/0.7] N_2_D+/N_2_H+/NH_3_ velocity dispersionkm/sphys.veloc.dispersionfloate_Sthin[0/0.09] Sthin uncertaintykm/sstat.errorfloatOID? Number identifier in Refmeta.idintnullabler_OIDReference ID (2)meta.ref;pos.framecharVmod[4/10.1]? HCO+ HILL5 model-derived systemic velocitykm/sphys.veloc;pos.heliocentricfloatnullablee_Vmod[0.007/0.03]? Vmod uncertaintykm/sstat.errorfloatnullableSigma[0.1/0.6]? HCO+ HILL5 velocity dispersionkm/sphys.veloc.dispersionfloatnullablee_Sigma[0.005/0.08]? Sigma uncertaintykm/sstat.errorfloatnullableVin[-0.6/0.4]? HCO+ HILL5 contraction velocity (3)km/sphys.velocfloatnullablee_Vin[0.01/0.2]? Vin uncertaintykm/sstat.errorfloatnullableTex[6.8/19.1]? HCO+ HILL5 excitation temperatureKphys.atmol.excitationfloatnullablee_Tex[0.1/0.8]? Tex uncertaintyKstat.errorfloatnullabletau[0.8/7]? HCO+ HILL5 optical depthphys.absorption.opticalDepthfloatnullablee_tau[0.1/0.8]? tau uncertaintystat.errorfloatnullableChi2[0.7/5.3]? HCO+ HILL5 reduced {chi}^2^ goodness of fit parameterstat.fit.chi2floatnullabledelV[-1.2/0.9]? Dimensionless asymmetry parameter ({delta}v) (4)stat.fit.paramfloatnullablee_delV[0.01/0.2]? delV uncertaintystat.errorfloatnullabledelV*[-1.2/1]? Modified asymmetry parameter (5)stat.fit.paramfloatnullablee_delV*[0.02/0.3]? delV* uncertaintystat.errorfloatnullableJ/ApJ/819/143/table4Continuum masses and stability of the Perseus coresrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSet"Starless" or "Protostellar"src.classcharNameSource designation or "Mean"meta.id;meta.maincharReff[0.01/0.2] Effective core radius from the continuum surveyspcphys.size.radiusfloatMass[0.2/7.2] Derived core masssolMassphys.massfloatTk[9/16.4] Gas kinetic temperature (1)Kphys.temperaturefloatSigNT[0.08/0.5]? Non-thermal velocity dispersionkm/sphys.veloc.dispersionfloatnullableMJ[0.5/3.7] Jeans masssolMassphys.massfloatM/MJ[0.2/5.8] Ratio of core mass to Jeans massphys.mass;arith.ratiofloat