J/ApJ/899/128ivo://CDS.VizieR/J/ApJ/899/128doi:10.26093/cds/vizier.18990128CDSKuhn M.A.Hillenbrand L.A.Carpenter J.M.Avelar Menendez A.R.2022-03-14T07:05:45Z2021-11-03T12:51:13ZCDS support team

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

cds-question@unistra.frstar-forming-regionsyoung-stellar-objectsradio-spectroscopyinfrared-photometryvisible-astronomyWe examine the clustering and kinematics of young stellar objects (YSOs) in the North America/Pelican Nebulae, as revealed by Gaia astrometry, in relation to the structure and motions of the molecular gas, as indicated in molecular-line maps. The Gaia parallaxes and proper motions allow us to significantly refine previously published lists of YSOs, demonstrating that many of the objects previously thought to form a distributed population turn out to be nonmembers. The members are subdivided into at least six spatio-kinematic groups, each of which is associated with its own molecular cloud component or components. Three of the groups are expanding, with velocity gradients of 0.3-0.5km/s/pc, up to maximum velocities of ~8km/s away from the groups' centers. The two known O-type stars associated with the region, 2MASS J20555125+4352246 and HD 199579, are rapidly escaping one of these groups, following the same position-velocity relation as the low-mass stars. We calculate that a combination of gas expulsion and tidal forces from the clumpy distribution of molecular gas could impart the observed velocity gradients within the groups. However, on a global scale, the relative motions of the groups do not appear either divergent or convergent. The velocity dispersion of the whole system is consistent with the kinetic energy gained due to gravitational collapse of the complex. Most of the stellar population has ages similar to the freefall timescales for the natal clouds. Thus, we suggest the nearly freefall collapse of a turbulent molecular cloud as the most likely scenario for star formation in this complex.2020ApJ...899..128Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/899/128CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/274 : Galactic O-Star Spectroscopic Survey (GOSSS) (Sota+, 2014)I/337 : Gaia DR1 (Gaia Collaboration, 2016)I/345 : Gaia DR2 (Gaia Collaboration, 2018)VIII/64 : Westerhout's Catalogue of 82 Discrete Sources (Westerhout, 1958)VII/7 : Lynds' Catalogue of Dark Nebulae (LDN) (Lynds 1962)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/AJ/123/2597 : H{alpha} stars and HH objects near BRCs (Ogura+, 2002)J/BaltA/15/483 : Vilnius photometry in LDN 935 (Laugalys+, 2006)J/ApJ/654/316 : X-ray sources in IC 1396N (Getman+, 2007)J/AJ/136/2413 : Galactic midplane Spitzer red sources (Robitaille+, 2008)J/MNRAS/384/1277 : H{alpha} emission line sources from IPHAS (Witham+, 2008)J/ApJ/697/787 : The NAN complex. I. IRAC observations (Guieu+, 2009)J/ApJ/697/1103 : Kinematics of Orion Nebula Cluster (Tobin+, 2009)J/ApJS/193/25 : The NAN complex. II. MIPS observations (Rebull+, 2011)J/MNRAS/426/2917 : X-rays sources in Trumpler 37 (Getman+, 2012)J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)J/AJ/147/46 : Properties of clumps in the NAN complex (Zhang+, 2014)J/A+A/589/A113 : PMS stars in h Per (Argiroffi+, 2016)J/ApJS/224/4 : GOSSS III 142 additional O-type systems (Maiz Apellaniz+,2016)J/MNRAS/460/2593 : Cygnus OB2 DANCe: Proper motion study (Wright+, 2016)J/A+A/602/A115 : X-ray survey of NGC7000/IC5070 (Damiani+, 2017)J/A+A/605/A85 : NGC 3293 Chandra X-ray observation (Preibisch+, 2017)J/A+A/619/A106 : 3D shape of Orion A from Gaia DR2 (Grossschedl+, 2018)J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)J/AJ/156/271 : The stellar membership of the Taurus SFR (Luhman, 2018)J/MNRAS/477/5191 : Ggalactic young stellar cluster lifetimes (Richert+, 2018)J/A+A/626/A80 : Census Rho Oph candidate members from Gaia DR2 (Canovas+,2019)J/A+A/630/A137 : Structure and kinematics of the Taurus region (Galli+, 2019)J/ApJ/878/111 : Members Serpens Molecular Cloud with Gaia DR2 (Herczeg+, 2019)J/ApJ/870/32 : Kinematics in young star clusters & associations (Kuhn+, 2019)J/A+A/624/A66 : Massive runaway and walkaway stars models (Renzo+, 2019)J/MNRAS/486/2477 : Catalogue of members of NGC 6530 (Wright+, 2019)J/MNRAS/493/2339 : Internal motions in OB-associations (Melnik+, 2020)J/A+A/633/A51 : Distances to molecular clouds in SFR (Zucker+, 2020)http://gea.esac.esa.int/archive : Gaia archiveshttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/899/128https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/899/128http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/899/128https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/899/128https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/899/128http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/899/128GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/899/128/table2 (Astrometrically validated members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/899/128/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/899/128/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/899/128/table2?GETtext/xml+votable180.050000true311.690166743.75319440.005555555555555556Cone search capability for table J/ApJ/899/128/table7 (New member candidates from Gaia)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/899/128/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/899/128/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/899/128/table7?GETtext/xml+votable180.050000true309.87987543.42683330.0055555555555555565/3498 3669 3671 3677 3840-3842 6/13311 13998-13999 14675 14681 14683 14705 15372-15374 15392-15393 15396https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/899/128?format=asciiOpticalInfraredMillimeterdefaultJ/ApJ/899/128/table2Astrometrically validated membersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia DR2 source designationmeta.id;meta.mainRA_ICRS[20/21] Hour of Right Ascension (ICRS) (G1)pos.eq.ra;meta.mainDE_ICRS[42/45] Degree of Declination (ICRS) (G1)pos.eq.dec;meta.mainGroupkinematic group assignment for each starmeta.idcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJ/899/128/table7New member candidates from GaiarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia DR2 source designationmeta.id;meta.mainRA_ICRS[20/21] Hour of Right Ascension (ICRS) (G1)pos.eq.ra;meta.mainDE_ICRS[40/46] Degree of Declination (ICRS) (G1)pos.eq.dec;meta.mainGroupkinematic group assignment for each star (1)meta.idchar