J/MNRAS/446/3797ivo://CDS.VizieR/J/MNRAS/446/3797doi:10.26093/cds/vizier.74463797CDSHur H.Park B.-G.Sung H.Bessell M.S.Lim B.Chun M.-Y.Sohn S.T.2024-08-14T20:19:12Z2015-11-24T15:53:30ZCDS support team

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

cds-question@unistra.fropen-star-clustersinfrared-photometryvisible-astronomybroad-band-photometryWe present deep UBVI_c_ photometric data of the young open cluster Westerlund 2. An abnormal reddening law of R_V,cl_=4.14+/-0.08 was found for the highly reddened early-type members (E(B-V)>=1.45), whereas a fairly normal reddening law of R_V,fg_=3.33+/-0.03 was confirmed for the foreground early-type stars (E(B-V)_fg_<1.05). The distance modulus was determined from zero-age main-sequence fitting to the reddening-corrected colour-magnitude diagram of the early-type members to be V_0_-M_V_=13.9+/-0.14 (random error) _-0.1_^+0.4^ (the upper limit of systematic error) mag (d=6.0+/-0.4_-0.3_^+1.2^kpc). To obtain te initial mass function, pre-main-sequence (PMS) stars were selected by identifying the optical counterparts of Chandra X-ray sources and mid-infrared emission stars from the Spitzer GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire) source catalogue. The initial mass function shows a shallow slope of {Gamma}=-1.1+/-0.1 down to log(m)=0.7. The total mass of Westerlund 2 is estimated to be at least 7400M_{sun}_. The age of Westerlund 2 from the main-sequence turn-on and PMS stars is estimated to be <~1.5Myr. We confirmed the existence of a clump of PMS stars located ~1-arcmin north of the core of Westerlund 2, but we could not find any clear evidence for an age difference between the core and the northern clump.2015MNRAS.446.3797Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/446/3797CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)J/A+A/466/137 : Westerlund 2 JHKs photometry (Ascenso+, 2007)J/AJ/102/642 : UBV photometry in Westerlund 2 (Moffat+, 1991)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/446/3797https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/446/3797http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/446/3797https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/446/3797https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/446/3797http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/446/3797GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/446/3797/table2 (The combined photometric data obtained with the CTIO 4m and 1m telescopes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/446/3797/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/446/3797/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/446/3797/table2?GETtext/xml+votable180.050000true155.7032917-57.73444440.0055555555555555566/37343 380262.367228618189496e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/446/3797?format=asciiOpticalInfrareddefaultJ/MNRAS/446/3797/table2The combined photometric data obtained with the CTIO 4m and 1m telescopesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintV-NIRindicates V-NIR colours in table6meta.ref.urlcharSeqSequential numbermeta.recordintprimaryRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainindexedDEJ2000Declination (J2000)pos.eq.dec;meta.mainVmag? Johnson V magnitudemagphot.mag;em.opt.Vfloatnullablee_Vmag? rms uncertainty on Vmagmagstat.error;phot.mag;em.opt.Vfloatnullableo_VmagNumber of observations for Vmagmeta.numberintImag? Cousins I magnitudemagphot.mag;em.opt.Ifloatnullablee_Imag? rms uncertainty on Imagmagstat.error;phot.mag;em.opt.Ifloatnullableo_ImagNumber of observations for Imagmeta.numberintU-B? Johnson U-B colour indexmagphot.color;em.opt.U;em.opt.Bfloatnullablee_U-B? rms uncertainty on U-Bmagstat.error;phot.color;em.opt.Ufloatnullableo_U-BNumber of observations for U-Bmeta.numberintB-V? Johnson B-V colour indexmagphot.color;em.opt.B;em.opt.Vfloatnullablee_B-V? rms uncertainty on B-Vmagstat.error;phot.color;em.opt.Bfloatnullableo_B-VNumber of observations for B-Vmeta.numberintV-I? Johnson-Cousins V-I colour indexmagphot.color;em.opt.V;em.opt.Ifloatnullablee_V-I? rms uncertainty on V-Imagstat.error;phot.color;em.opt.Vfloatnullableo_V-INumber of observations for V-Imeta.numberintRem[123DEUXe ] Remarks (1)meta.notecharMSP? ID in Moffat et al. (1991, Cat. J/AJ/102/642), Cl* Westerlund 2 MSP NNN in Simbadmeta.idintnullableA07? ID in Ascenso et al. (2007, Cat. J/A+A/466/137), Cl* Westerlund 2 AAB NNNN in Simbadmeta.idintnullable2MASS2MASS designation (HHMMSSss+DDMMSSs)meta.idcharGLIMPSEGLIMPSE designation (GLLL.llll+BB.bbbb)meta.idcharJ/MNRAS/446/3797/table6*V-NIR colours and the reddening-corrected magnitude and colours of the early-type starsV-H? V-H colour indexmagphot.color;em.opt.V;em.IR.HfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqSequential numbermeta.recordintV-J? V-J colour indexmagphot.color;em.opt.V;em.IR.Jfloatnullablee_V-J? rms uncertainty on V-Jmagstat.error;phot.color;em.opt.Vfloatnullablee_V-H? rms uncertainty on V-Hmagstat.error;phot.color;em.opt.VfloatnullableV-Ks? V-Ks colour indexmagphot.color;em.opt.V;em.IR.Kfloatnullablee_V-Ks? rms uncertainty on V-Ksmagstat.error;phot.color;em.opt.VfloatnullableV0magReddening-corrected V magnitude (1)magphot.mag.reddFree;em.opt.Vfloat(U-B)0Reddening-corrected U-B colour indexmagphot.color;em.opt.U;em.opt.Bfloat(B-V)0Reddening-corrected B-V colour indexmagphot.color;em.opt.B;em.opt.Vfloat(V-I)0? Reddening-corrected V-I colour indexmagphot.color;em.opt.V;em.opt.Ifloatnullable(V-J)0? Reddening-corrected V-J colour indexmagphot.color;em.opt.V;em.IR.Jfloatnullable(V-H)0? Reddening-corrected V-H colour indexmagphot.color;em.opt.V;em.IR.Hfloatnullable(V-Ks)0? Reddening-corrected V-Ks colour indexmagphot.color;em.opt.V;em.IR.KfloatnullableRem[BDUb ] Remarks (2)meta.notechar