J/ApJ/807/27ivo://CDS.VizieR/J/ApJ/807/27doi:10.26093/cds/vizier.18070027CDSCottaar M.Covey K.R.Foster J.B.Meyer M.R.Tan J.C.Nidever D.L.,Drew Chojnowski S.da Rio N.Flaherty K.M.Frinchaboy P.M.Majewski S.,Skrutskie M.F.Wilson J.C.Zasowski G.2017-09-20T05:13:46Z2015-12-10T13:30:10ZCDS support team

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

cds-question@unistra.fropen-star-clustersradial-velocityMost field stars will have encountered the highest stellar density and hence the largest number of interactions in their birth environment. Yet the stellar dynamics during this crucial phase are poorly understood. Here we analyze the radial velocities measured for 152 out of 380 observed stars in the 2-6Myr old star cluster IC 348 as part of the SDSS-III APOGEE. The radial velocity distribution of these stars is fitted with one or two Gaussians, convolved with the measurement uncertainties including binary orbital motions. Including a second Gaussian improves the fit; the high-velocity outliers that are best fit by this second component may either (1) be contaminants from the nearby Perseus OB2 association, (2) be a halo of ejected or dispersing stars from IC 348, or (3) reflect that IC 348 has not relaxed to a Gaussian velocity distribution. We measure a velocity dispersion for IC 348 of 0.72+/-0.07km/s (or 0.64+/-0.08km/s if two Gaussians are fitted), which implies a supervirial state, unless the gas contributes more to the gravitational potential than expected. No evidence is found for a dependence of this velocity dispersion on distance from the cluster center or stellar mass. We also find that stars with lower extinction (in the front of the cloud) tend to be redshifted compared with stars with somewhat higher extinction (toward the back of the cloud). This data suggest that the stars in IC 348 are converging along the line of sight. We show that this correlation between radial velocity and extinction is unlikely to be spuriously caused by the small cluster rotation of 0.024+/-0.013km/s/arcmin or by correlations between the radial velocities of neighboring stars. This signature, if confirmed, will be the first detection of line of sight convergence in a star cluster. Possible scenarios for reconciling this convergence with IC 348's observed supervirial state include: (a) the cluster is fluctuating around a new virial equilibrium after a recent disruption due to gas expulsion or a merger event, or (b) the population we identify as IC 348 results from the chance alignment of two sub-clusters converging along the line of sight. Additional measurements of tangential and radial velocities in IC 348 will be important for clarifying the dynamics of this region and informing models of the formation and evolution of star clusters.2015ApJ...807...27Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/807/27CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/197 : ISM towards IC 348 and Per OB2 (Cernis, 1993)J/ApJ/799/136 : IN-SYNC. II. Candidate young stars in NGC1333 (Foster+, 2015)J/ApJ/794/125 : IN-SYNC. I. APOGEE stellar parameters (Cottaar+, 2014)J/A+A/563/A94 : Kinematics of the Gamma Vel cluster (Jeffries+, 2014)J/MNRAS/437/906 : Cl* IC 348 H 254 VRI light curves (Ripepi+, 2014)J/MNRAS/434/806 : Pre-main-sequence isochrones. II. SFR (Bell+, 2013)J/AJ/145/66 : Spitzer light curves of YSOs in IC 348 (Flaherty+, 2013)J/A+A/554/A55 : C^18^O(1-0) and N_2_H^+^(1-0) in L1495/B213 (Hacar+, 2013)J/A+A/539/A64 : X-ray data for IC 348 young stars (Alexander+, 2012)J/A+A/537/A135 : X-ray view of IC348 (Stelzer+, 2012)J/ApJ/754/44 : The AstraLux Large M-dwarf Survey (Janson+ 2012)J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/AJ/138/703 : Deep MIPS observations of IC 348 nebula (Currie+, 2009)J/AJ/134/411 : Properties of IC 348 members (Muench+, 2007)J/AJ/131/1574 : Infrared photometry of IC348 members (Lada+, 2006)J/ApJ/649/862 : IR phot. of IC 348 pre-main-sequence stars (Cieza+, 2006)J/ApJ/597/555 : IR photometry of IC 348 young brown dwarfs (Mainzer+, 2003)J/A+A/409/147 : J magnitude of IC 348 brown dwarfs (Preibisch+, 2003)J/ApJ/593/1093 : IC 348 membership (Luhman+, 2003)J/AJ/122/866 : X-ray sources in IC 348 from Chandra (Preibisch+, 2001)J/ApJ/541/977 : HST observations of low-mass stars in IC 348 (Najita+, 2000)J/ApJ/525/466 : Young low-mass stars & brown dwarfs in IC 348 (Luhman+, 1999)J/A+AS/137/305 : IC 348 proper motion catalogue (Scholz+, 1999)J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)http://www.sdss3.org/ : SDSS-III home pagehttp://www.astro.ufl.edu/insync/ : IN-SYNC program home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/807/27https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/807/27http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/807/27https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/807/27https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/807/27http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/807/27GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/807/27/stars (List of stars; table added by CDS)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/807/27/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/807/27/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/807/27/stars?GETtext/xml+votable180.050000true50.904916730.94266670.0055555555555555565/115 118 214 215 384 386 5350 5356 5359 5701 5909 5952 6/455 466 484 485 496 497 854 855 880 881 883 884 885 886 1540 1542 1548 21391 21406 21413 21428 21430 21431 21432 21433 21435 21480 21482 21483 22270 22271 22442 22443 22801 22848 22850 23645 23814 23816 23817https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/807/27?format=asciiOpticaldefaultJ/ApJ/807/27/table1*Radial velocities of 4771 stars in IC 3482MASS2MASS name (HHMMSSss+DDMMSSs; J2000)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian date of the observationdtime.epochdoubleRV[-2791/2272] Radial velocitykm/sphys.veloc;pos.heliocentricdoubleRVc[-2791/2272]? Corrected Radial velocity (1)km/sphys.veloc;pos.heliocentricdoublenullablee_RVc[0.002/76749]? Uncertainty in RVckm/sstat.errordoublenullableJ/ApJ/807/27/starsList of stars; table added by CDSrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASS2MASS name (HHMMSSss+DDMMSSs; J2000)meta.id;meta.maincharNrvNumber of radial velocity measures for this starmeta.numberintnullablePapIDisplay data from Paper I (Cottaar+, 2014, J/ApJ/794/125) if anymeta.ref.urlintnullableVPInteractive plot of radial velocities (for stars with more than 2 measures)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from 2MASS names (right ascension part)degpos.eq.ra;meta.main_DEPositions from 2MASS names (declination part)degpos.eq.dec;meta.main