J/ApJ/833/97ivo://CDS.VizieR/J/ApJ/833/97doi:10.26093/cds/vizier.18330097CDSKeown J.Schnee S.Bourke T.L.Di Francesco J.Friesen R.Caselli P.,Myers P.Williger G.Tafalla M.2017-06-30T05:47:57Z2017-05-05T13:46:18ZCDS support team

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

cds-question@unistra.frmolecular-cloudsmillimeter-astronomysubmillimeter-astronomyAlthough surveys of infall motions in dense cores have been carried out for years, few surveys have focused on mapping infall across cores using multiple spectral-line observations. To fill this gap, we present IRAM 30m telescope maps of N_2_H^+^(1-0), DCO^+^(2-1), DCO^+^(3-2), and HCO^+^(3-2) emission toward two prestellar cores (L492 and L694-2) and one protostellar core (L1521F). We find that the measured infall velocity varies with position across each core and choice of molecular line, likely as a result of radial variations in core chemistry and dynamics. Line-of-sight infall speeds estimated from DCO^+^(2-1) line profiles can decrease by 40-50m/s when observing at a radial offset >=0.04pc from the core's dust continuum emission peak. Median infall speeds calculated from all observed positions across a core can also vary by as much as 65m/s, depending on the transition. These results show that while single-pointing, single-transition surveys of core infall velocities may be good indicators of whether a core is either contracting or expanding, the magnitude of the velocities they measure are significantly impacted by the choice of molecular line, proximity to the core center, and core evolutionary state.2016ApJ...833...97Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/833/97CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/584/A91 : Dense cores in Aquila from Herschel (Konyves+, 2015)J/A+A/487/993 : MAMBO Mapping of c2d Clouds and Cores (Kauffmann+, 2008)J/ApJS/175/277 : Submillimeter-Continuum SCUBA detections (Di Francesco+, 2008)J/ApJ/664/928 : Starless cores in HCN(J=1-0) (Sohn+ 2007)J/A+A/432/369 : Leiden Atomic and Molecular Database (LAMDA) (Schoeier+, 2005)J/ApJS/153/523 : Starless cores in CS(3-2) and DCO^+^(2-1) lines (Lee+, 2004)J/ApJ/578/914 : Low-mass stars in Taurus (Hartmann, 2002)J/ApJ/526/788 : Survey of infall motions toward starless cores (Lee+, 1999)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/833/97https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/833/97http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/833/97https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/833/97https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/833/97http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/833/97GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/833/97/table1 (Summary of dense core properties from the literature)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/833/97/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/833/97/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/833/97/table1?GETtext/xml+votable180.050000true273.9625-3.740.0055555555555555566/1075 29661 30575https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/833/97?format=asciiRadiodefaultJ/ApJ/833/97/table1Summary of dense core properties from the literatureSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCore identifiermeta.id;meta.maincharprimaryVinDisplay the velocity measurements for this coremeta.ref.urlcharDist[140/250] Distance from Crapsi+ 2005ApJ...619..379Cpcpos.distance;pos.heliocentricintRadRadius in arcsecarcsecphys.angSize;srcfloatr_RadReference for rad (1)meta.ref;pos.framecharRadpc[0.05/0.2] Radius in parsecpcphys.size.radiusfloatMassMasssolMassphys.massfloatr_MassReference for Mass (1)meta.refcharD/H[0.05/0.3] deuterium fractionation N(N_2_D^+^)/N(N_2_H^+^) from Crapsi+ 2005ApJ...619..379Cstat.fit.omcfloate_D/H[0.01/0.05] D/H uncertaintystat.error;phys.abundfloatHCO+[0.1/0.5]? HCO^+^ (3-2) infall velocity from Schnee+ 2013ApJ...777..121Skm/sphys.velocfloatnullablee_HCO+? HCO+ uncertaintykm/sstat.errorfloatnullablef_HCO+[d] Flag on L492 infall asymmetry in HCO^+^ (3-2) (2)meta.codecharCCatDisplay data from Kauffmann+, 2008, J/A+A/487/993 and Sohn+, 2007, J/ApJ/664/928meta.ref.urlintnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/833/97/infallInfall/expansion measurements for L492 , L694-2 and L1521FrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSimbad column added by the CDSmeta.id;meta.maincharSeqSpectrum observation numbermeta.numberintdRAOffset from central pointing, in RA, arcsec (1)arcsecpos.eq.ra;arith.diffintdDEOffset from central pointing, in DE, arcsec (1)arcsecpos.eq.dec;arith.diffintdVin1[-0.2/0.2] N2H (1-0) infall/expansion velocity (G1)km/sphys.velocfloate_dVin1[0/2.5] Uncertainty in dVin1km/sstat.errorfloatSNR1[2/130] N2H (1-0) spectrum signal to noise ratiostat.snrfloatdVin2[-0.3/0.5]? DCO+ (2-1) infall/expansion velocity (G1)km/sphys.velocfloatnullablee_dVin2[0/7]? Uncertainty in dVin2km/sstat.errorfloatnullableSNR2[2/68]? DCO+ (2-1) spectrum signal to noise ratiostat.snrfloatnullabledVin3[-0.3/0.6]? DCO+ (3-2) infall/expansion velocity (G1)km/sphys.velocfloatnullablee_dVin3[0/9]? Uncertainty in dVin3km/sstat.errorfloatnullableSNR3[2/47]? DCO+ (3-2) spectrum signal to noise ratiostat.snrfloatnullabledVin4[-0.2/0.3]? HCO+ (3-2) infall/expansion velocity (G1)km/sphys.velocfloatnullablee_dVin4[0/6]? Uncertainty in dVin4km/sstat.errorfloatnullableSNR4[2/25]? HCO+ (3-2) spectrum signal to noise ratiostat.snrfloatnullable