J/AJ/157/109ivo://CDS.VizieR/J/AJ/157/109doi:10.26093/cds/vizier.51570109CDSKim D.Lu J.R.Konopacky Q.Chu L.Toller E.Anderson J.,Theissen C.A.Morris M.R.2019-07-24T11:35:39Z2019-07-05T07:55:20ZCDS support team

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

cds-question@unistra.fropen-star-clustersmultiple-starsproper-motionshst-photometryThe Orion Nebula Cluster (ONC) is the nearest site of ongoing massive star formation, which allows us to study the kinematics and dynamics of the region in detail and constrain star formation theories. Using HST ACS/WFPC2/WFC3IR and Keck II NIRC2 data, we have measured the proper motions of 701 stars within an ~6'x6' field of view around the center of the ONC. We have found more than 10 escaping star candidates, concentrated predominantly at the core of the cluster. The proper motions of the bound stars are consistent with a normal distribution, albeit elongated north-south along the Orion filament, with proper-motion dispersions of ({sigma}_{mu},{alpha}_*, {sigma}_{mu},{delta}_)=(0.83+/-0.02, 1.12+/-0.03) mas/yr or intrinsic velocity dispersions of ({sigma}_v,{alpha}_*, {sigma}_v,{delta}_)=(1.57+/-0.04, 2.12+/-0.06) km/s assuming a distance of 400 pc to the ONC. The cluster shows no evidence for tangential-to-radial anisotropy. Our velocity dispersion profile agrees with the prediction from the observed stellar + gas density profile from Da Rio et al. (2014ApJ...795...55D, 2017ApJ...845..105D), indicating that the ONC is in virial equilibrium. This finding suggests that the cluster was formed with a low star formation efficiency per dynamical timescale based on comparisons with current star formation theories. Our survey also recovered high-velocity IR sources BN, x and n in the BN/KL region. The estimated location of the first two sources ~500 yr ago agrees with that of the radio source I, consistent with their proposed common origin from a multistellar disintegration. However, source n appears to have a small proper motion and is unlikely to have been involved in the event.2019AJ....157..109Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/157/109CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+AS/118/503 : Proper motions of stars in Ori Nebula (Tian+ 1996)J/AJ/111/846 : Orion HST survey (O'Dell+ 1996)J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)J/AJ/125/277 : High proper motions in central Orion nebula (O'dell+, 2003)J/AJ/127/3456 : Internal velocities in the Orion Nebula (Doi+, 2004)J/AJ/136/2136 : HST/ACS Atlas of Great Orion Nebula proplyds (Ricci+, 2008)J/ApJ/676/1109 : Velocities of stars in the Orion Nebula ClusterJ/ApJ/697/1103 : Kinematics of Orion Nebula Cluster (Tobin+, 2009)J/ApJ/722/1092 : Optical photometry of the ONC. II. (Da Rio+, 2010)J/A+A/534/A10 : HST/NICMOS III imaging in Orion Nebula ClusterJ/ApJ/733/50 : Mid-IR photometric monitoring of the ONCJ/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)J/AJ/150/108 : Spectroscopy and HST imaging in ONC (O'Dell+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/157/109https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/157/109http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/157/109https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/157/109https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/157/109http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/157/109GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/157/109/table1 (HST observation)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/157/109/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/157/109/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/157/109/table1?GETtext/xml+votable180.050000true83.814375-5.40184720.005555555555555556Cone search capability for table J/AJ/157/109/table3 (Proper motion measurements)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/157/109/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/157/109/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/157/109/table3?GETtext/xml+votable180.050000true83.85346518-5.36602620.0055555555555555566/21438 21439 22805https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/157/109?format=asciidefaultJ/AJ/157/109/table1HST observationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEpoch[1/11] Epoch numbermeta.id;meta.mainintDateDate of the observationtime.epochnullableRAJ2000Hour of Right Ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000) (1)pos.eq.dec;meta.mainInstInstrumentmeta.id;instrcharFiltFiltermeta.id;instr.filtercharExpTime[40/500] Exposure timestime.duration;obs.exposurefloatGO-ID[5976/13826] Proposal IDmeta.id;obsintPIPrincipal investigator's nameobs.observercharJ/AJ/157/109/table3Proper motion measurementsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[1/715] Internal source identifiermeta.id;meta.mainintRAJ2000Right Ascension in decimal degrees (J2000, Epoch=J2015.5)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000, Epoch=J2015.5)degpos.eq.dec;meta.mainpmRA[-29.21/26.83] Proper motion along RA, {mu}_{alpha}_*cos({delta})mas/yrpos.pm;pos.eq.rafloate_pmRA[0/3.98] Uncertainty in pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDE[-33.83/29.69] Proper motion along DE, {mu}_{delta}_mas/yrpos.pm;pos.eq.decfloate_pmDE[0/6.81] Uncertainty in pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatNdet[2/9] Number of detections within the time baselinemeta.numberintDt[4.1/20.1] Time baseline {Delta}tyrtime.epochfloatF139[9.62/20.34]? F139 Vega-mag photometrymagphot.mag;em.IRfloatnullableNote[1/6]? Note (1)meta.noteintnullable