J/A+A/625/A103ivo://CDS.VizieR/J/A+A/625/A103doi:10.26093/cds/vizier.36250103CDSvan der Tak F.F.S.Shipman R.F.Jacq T.Herpin F.Braine J.Wyrowski F.2019-11-11T22:00:00Z2019-06-04T14:15:55ZCDS support team

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

cds-question@unistra.frstar-forming-regionsspectroscopyThe physical conditions during high-mass star formation are poorly understood. Outflow and infall motions have been detected around massive protostellar objects, but their dependence on mass, luminosity, and age is unclear. In addition, physical conditions and molecular abundances are often estimated using simple assumptions such as spherical shape and chemical homogeneity, which may limit the accuracy of the results. We aim to characterize the dust and gas distribution and kinematics of the envelopes of high-mass protostars. In particular, we search for infall motions, abundance variations, and deviations from spherical symmetry, using Herschel data from the WISH program. We used HIFI maps of the 987GHz H_2_O 2_02_-1_11_ emission to measure the sizes and shapes of 19 high-mass protostellar envelopes. To identify infall, we used HIFI spectra of the optically thin C^18^O 9-8 and H_2_^18^O 1_11_-0_00_ lines. The high-J C^18^O line traces the warm central material and redshifted H_2_^18^O 1_11_-0_00_ absorption indicates material falling onto the warm core. We probe small-scale chemical differentiation by comparing H_2_O 752 and 987GHz spectra with those of H_2_^18^O. Our measured radii of the central part of the H_2_O 2_02_-1_11_ emission are 30-40% larger than the predictions from spherical envelope models, and axis ratios are <2, which we consider good agreement. For 11 of the 19 sources, we find a significant redshift of the H_2_^18^O 1_11_-0_00_ line relative to C^18^O 9-8. The inferred infall velocities are 0.6-3.2km/s, and estimated mass inflow rates range from 7x10^-5^ to 2x10^-2^M_{sun}_/yr. The highest mass inflow rates seem to occur toward the sources with the highest masses, and possibly the youngest ages. The other sources show either expanding motions or H_2_^18^O lines in emission. The H_2_^18^O 1_11_-0_00_ line profiles are remarkably similar to the differences between the H_2_O 2_02_-1_11_ and 2_11_-2_02_ profiles, suggesting that the H_2_^18^O line and the H_2_O 2_02_-1_11_ absorption originate just inside the radius where water evaporates from grains, typically 1000-5000au from the center. In some sources, the H_2_^18^O line is detectable in the outflow, where no C^18^O emission is seen. Together, the H_2_^18^O absorption and C^18^O emission profiles show that the water abundance around high-mass protostars has at least three levels: low in the cool outer envelope, high within the 100K radius, and very high in the outflowing gas. Thus, despite the small regions, the combination of lines presented in this work reveals systematic inflows and chemical information about the outflows.2019A&A...625A.103Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/625/A103CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/720/1055 : VBLA observations of W51 Main/South (Sato+, 2010)J/A+A/579/A91 : ATLASGAL inner Galaxy massive cold dust clumps (Wienen+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/625/A103https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/625/A103http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/625/A103https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/625/A103https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/625/A103http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/625/A103GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/625/A103/table1 (Source sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/625/A103/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/625/A103/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/625/A103/table1?GETtext/xml+votable180.050000true84.80458335.7638890.005555555555555556Cone search capability for table J/A+A/625/A103/list (List of fits spectra and datacubes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/625/A103/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/625/A103/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/625/A103/list?GETtext/xml+votable180.050000true307.3533840.188510.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/625/A1036/3649 14317 14689 14704 24554 28912 29097 29101 29103 29513 30259 30262 30269 30318 30694 41812 42211 42456-42457https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/625/A103?format=asciidefaultJ/A+A/625/A103/table1Source sampleTypeTypesrc.classcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn_Type[*] Note on Type (1)meta.notecharSpList of fits files associated to this sourcemeta.ref.urlcharSourceSource namemeta.id;meta.maincharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainLbolBolometric luminositysolLumphys.luminositydoubleDistDistancekpcpos.distancefloatMenvEnvelope masssolMassphys.massintr_DistDistance reference (2)meta.ref;pos.frameintSNameSimbad namemeta.idcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/625/A103/listList of fits spectra and datacubesspShow the spectrummeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNy? Number of pixels along Y-axis for the datacubesmeta.numberintnullableNz? Number of slices for the datacubesmeta.numberintnullableObs.dateObservation datestime.epoch;obsnullablebFreq? Lower value of frequency interval for spectraHzem.freq;stat.mindoublenullableBFreq? Upper value of frequency interval for spectraHzem.freq;stat.maxdoublenullabledFreq? Frequency resolution for spectraHzspect.resolutionintnullablebVel? Lower value of velocity interval for datacubesm/sphys.velocdoublenullableBVel? Upper value of velocity interval for datacubesm/sphys.velocdoublenullabledVel? Velocity resolution for datacubesm/sspect.resolutiondoublenullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitsAssocDataAssociated Data web pagemeta.ref.urlchar