J/AJ/150/100ivo://CDS.VizieR/J/AJ/150/100doi:10.26093/cds/vizier.51500100CDSKoenig X.Hillenbrand L.A.Padgett D.L.DeFelippis D.2017-06-21T08:22:08Z2016-03-15T12:32:30ZCDS support team

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

cds-question@unistra.frstellar-associationsyoung-stellar-objectsinfrared-photometryWe have conducted a sensitive search down to the hydrogen burning limit for unextincted stars over ~200 square degrees around Lambda Orionis and 20 square degrees around Sigma Orionis using the methodology of Koenig & Leisawitz (2014ApJ...791..131K; K14). From WISE and 2MASS data we identify 544 and 418 candidate young stellar objects (YSOs) in the vicinity of {lambda} and {sigma} respectively. Based on our followup spectroscopy for some candidates and the existing literature for others, we found that ~80% of the K14-selected candidates are probable or likely members of the Orion star-forming region. The yield from the photometric selection criteria shows that WISE sources with K_S_-w3>1.5mag and K_S_ between 10 and 12mag are most likely to show spectroscopic signs of youth, while WISE sources with K_S_-w3>4mag and K_s_>12 were often active galactic nuclei when followed up spectroscopically. The population of candidate YSOs traces known areas of active star formation, with a few new "hot spots" of activity near Lynds 1588 and 1589 and a more dispersed population of YSOs in the northern half of the HII region bubble around {sigma} and {epsilon} Ori. A minimal spanning tree analysis of the two regions to identify stellar groupings finds that roughly two-thirds of the YSO candidates in each region belong to groups of 5 or more members. The population of stars selected by WISE outside the MST groupings also contains spectroscopically verified YSOs, with a local stellar density as low as 0.5 stars per square degree.2015AJ....150..100Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/150/100CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/mk : Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)II/328 : AllWISE Data Release (Cutri+ 2013)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)V/73 : Emission-Line Stars of the Orion Population (Herbig+ 1988)J/MNRAS/435/1671 : SCUBA-2 850um survey in {sigma} Ori (Williams+, 2013)J/ApJ/754/30 : VISTA IR photometry of {sigma} Ori (Pena Ramirez+, 2012)J/ApJ/743/64 : Deep infrared photometry of {sigma} Ori (Bejar+, 2011)J/A+A/530/A150 : XMM observations of {lambda} Ori (Franciosini+, 2011)J/ApJS/191/389 : Photometric monitoring in {sigma} Ori cluster (Cody+, 2010)J/A+A/521/A45 : X-ray detections in the {sigma} Ori (Caballero+, 2010)J/A+A/493/931 : MAD observations of {sigma} Ori (Bouy+, 2009)J/ApJ/688/362 : Disks around brown dwarfs in {sigma} Ori (Luhman+, 2008)J/A+A/488/167 : {sigma} Ori and {lambda} Ori low-mass stars (Sacco+, 2008)J/A+A/485/931 : Young stars and brown dwarfs in Ori OB1b (Caballero+, 2008)J/MNRAS/385/2210 : Spectroscopy around lam Ori and sig Ori (Maxted+, 2008)J/A+A/470/191 : Mid-IR and radio interferometry of S Ori (Wittkowski+, 2007)J/A+A/446/501 : XMM observations of sigma Ori cluster (Franciosini+, 2006)J/MNRAS/356/1583 : RV of Sigma Ori low-mass candidate membersJ/MNRAS/356/89 : {sigma} Ori low-mass stars (Kenyon+, 2005)J/ApJ/610/1064 : Substellar population of {lambda} Ori (Barrado+, 2004)J/AN/325/705 : RIJHKs of low-mass stars in sigma Ori (Bejar+, 2004)J/AJ/128/2316 : BVRIJHKs photometry in {sigma} Ori cluster (Sherry+, 2004)J/AJ/123/387 : VRI photometry of {lambda} Ori SFR (Dolan+, 2002)J/AJ/121/2124 : {lambda} Ori PMS stars photometry (Dolan+, 2001)J/AJ/118/2409 : VRI photometry of {lambda} Ori PMS stars (Dolan+, 1999)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/150/100https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/150/100http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/150/100https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/150/100https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/150/100http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/150/100GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/150/100/yso (WISE YSO candidates in sigma Ori , and in lambda Ori)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/150/100/yso?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/150/100/yso?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/150/100/yso?GETtext/xml+votable180.050000true81.75814194-1.514806110.0055555555555555565/5714 5715 5721 5748 5749 5751 5899 5926 5929 5934 5946 6023 6/22807 22813 22815 22849 22850 22851 22852 22854 22855 22872 22874 22875 22880 22881 22883 22892 22896 22897 22898 22907 22989 22990 22991 23001 23002 23003 23009 23013 23014 23015 23021 23025 23026 23027 23030 23031 23033 23034 23037 23038 23377 23382 23383 23562 23563 23564 23566 23584 23585 23587 23588 23590 23591 23600 23601 23609 23611 23615 23681 23685 23686 23689 23690 23691 23693 23694 23695 23697 23698 23699 23700 23702 23703 23709 23710 23711 23714 23715 23720 23721 23722 23725 23726 23727 23728 23730 23731 23740 23744 23750 23753 23754 23755 23757 23759 23777 23778 23782 23783 23789 23790 23792 23795 23798 23800 23801 23802 24066 24068 24070 24073 24076 24077 24079 24080 24081 24085 24086 24112 24118 24120 24121 24128 24130 241348.157980699529898e-21 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/150/100?format=asciiInfrareddefaultJ/AJ/150/100/ysoWISE YSO candidates in sigma Ori , and in lambda OriClYSO classification (1)meta.code.class;src.classcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFieldField (sigma Orionis or lambda Orionis)meta.id.parentcharWISEAllWISE catalog designation (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainJmag[8.6/18.7]? 2MASS J band magnitudemagphot.mag;em.IR.Jdoublenullablee_Jmag[0.01/0.3]? Uncertainty in Jmagmagstat.error;phot.mag;em.IR.JdoublenullableHmag[7.9/16.5]? 2MASS H band magnitudemagphot.mag;em.IR.Hdoublenullablee_Hmag[0.01/0.3]? Uncertainty in Hmagmagstat.error;phot.mag;em.IR.HdoublenullableKmag[7.1/16.1]? 2MASS Ks band magnitudemagphot.mag;em.IR.Kdoublenullablee_Kmag[0.01/0.2]? Uncertainty in Kmagmagstat.error;phot.mag;em.IR.KdoublenullableW1mag[6.5/15.4]? WISE W1 3.4{mu}m band magnitudemagphot.mag;em.IR.3-4umdoublenullablee_W1mag[0.02/0.2]? Uncertainty in W1magmagstat.error;phot.mag;em.IR.3-4umdoublenullableW2mag[5.6/13.2]? WISE W2 4.6{mu}m band magnitudemagphot.mag;em.IR.4-8umdoublenullablee_W2mag[0.01/0.2]? Uncertainty in W2magmagstat.error;phot.mag;em.IR.4-8umdoublenullableW3mag[-4.5/12]? WISE W3 12{mu}m band magnitudemagphot.flux.density;em.IR.8-15umdoublenullablee_W3mag[0.01/0.5]? Uncertainty in W3magmagstat.error;phot.mag;em.IR.8-15umdoublenullableW4mag[-1.7/9.2]? WISE W4 22{mu}m band magnitudemagphot.flux.density;em.IR.15-30umdoublenullablee_W4mag[0.01/0.6]? Uncertainty in W4magmagstat.error;phot.mag;em.IR.15-30umdoublenullablealpha[-3.51/2.4]? 2MASS-WISE spectral index {alpha}spect.indexfloatnullableEWHa[-181/16]? H{alpha} line equivalent width (in {AA}) (2)0.1nmspect.line.eqWidth;em.line.HalphafloatnullableEWCaII[-47.1/3.1]? CaII 854.2nm line equivalent width (in {AA}) (2)0.1nmspect.line.eqWidth;em.opt.IfloatnullableMmLikelihood of membership in the Orion star-forming region (y=yes, m=maybe, n=no, -=unknown) (3)meta.code.membercharSpTSpectral type where available in the literaturesrc.spTypecharr_SpTReference for SpT (4)meta.ref;pos.framechar