J/A+A/416/555ivo://CDS.VizieR/J/A+A/416/555doi:10.26093/cds/vizier.34160555CDSLopez-Marti B.Eisloeffel J.Scholz A.Mundt R.2004-09-23T06:34:16Z2004-09-23T06:34:01ZCDS support team

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

cds-question@unistra.frmolecular-cloudspre-main-sequence-starsinfrared-photometryWe present the results of a multiband survey for brown dwarfs in the Chamaeleon I dark cloud with the Wide Field Imager (WFI) camera at the ESO/MPG 2.2-m telescope on La Silla (Chile) on 28-May to 03-Jun 1999. The survey has revealed a substantial population of brown dwarfs in this southern star-forming region. Candidates were selected from R, I and H{alpha} imaging observations. We also observed in two medium-band filters, M855 and M915, for spectral type determination. The former filter covers a wavelength range containing spectral features characteristic of M-dwarfs, while the latter lies in a relatively featureless wavelength region for these late-type objects. A correlation was found between spectral type and (M855-M915) colour index for mid- to late M-type objects and early L-type dwarfs. With this method, we identify most of our object candidates as being of spectral type M5 or later. Our results show that there is no strong drop in the number of objects for the latest spectral types, hence brown dwarfs may be as abundant as low-mass stars in this region. Also, both kind of objects have a similar spatial distribution. We derive an index {alpha}=0.6+/-0.1 of the mass function in this region of dispersed star formation, in good agreement with the values obtained in other star forming regions and young clusters. Some of the brown dwarfs have strong H{alpha} emission, suggesting mass accretion. For objects with published infrared photometry, we find that strong H{alpha} emission is related to a mid-infrared excess, indicative of the existence of a circumstellar disk.2004A&A...416..555Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/416/555CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/357/219 : ISOCAM observations in Cha I. (Persi+, 2000)J/AJ/121/974 : JHK photometry in Cha I (Gomez+, 2001)J/AJ/124/1001 : JHKs photometry of Cha I variables (Carpenter, 2002)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/416/555https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/416/555http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/416/555https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/416/555https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/416/555http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/416/555GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/416/555/table4 (Candidate low-mass members of ChaI)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/416/555/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/416/555/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/416/555/table4?GETtext/xml+votable180.050000true167.997083-77.5106110.0055555555555555566/36956-36957 37128https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/416/555?format=asciiInfrareddefaultJ/A+A/416/555/table4Candidate low-mass members of ChaIrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIRExistence of Infrared photometrymeta.refcharChaI[400,760] Source numbermeta.id;meta.mainintprimaryn_ChaI[efg] Individual notes (G1)meta.notecharRAJ2000Right Ascension J2000 (hours)pos.eq.ra;meta.mainDEJ2000Declination J2000 (degrees)pos.eq.dec;meta.mainRmagRed magnitude (reduced with Landolt standards)magphot.mag;em.opt.Rfloatu_Rmag[;:] Uncertainty flag on Rmag (1)meta.code.errorcharImagI magnitudemagphot.mag;em.opt.Ifloatu_Imag[;:] Uncertainty flag on Imagmeta.code.errorcharHalphaH-alpha magnitudemagphot.flux;em.line.Halphafloatu_Halpha[;:] Uncertainty flag on Halphameta.code.errorcharM855Magnitude in medium-band filter 855/20nmmagphot.mag;em.opt.Ifloatu_M855[;:] Uncertainty flag on M855meta.code.errorcharM915Magnitude in medium-band filter 915/28nmmagphot.mag;em.opt.Ifloatu_M915[;:] Uncertainty flag on M915meta.code.errorcharSpTypeSpectral class (2)src.spTypecharClassObject classificationsrc.classcharOtherNamesOther names, as a comma-separated list (3)meta.idcharJ/A+A/416/555/table6Infrared photometry for candidate low-mass membersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintChaI[400,760] Source numbermeta.id;meta.mainintn_ChaI[b] Individual notes (G1)meta.notecharJDmag? DENIS J magnitudemagphot.mag;em.IR.JfloatnullableKDmag? DENIS K magnitudemagphot.mag;em.IR.KfloatnullableJmag? J magnitudemagphot.mag;em.IR.JfloatnullableHmag? H magnitudemagphot.mag;em.IR.HfloatnullableKmag? K magnitudemagphot.mag;em.IR.KfloatnullableLmag? L magnitude (3.5um)magphot.mag;em.IR.3-4umfloatnullableF6.7um? ISOCAM infrared flux at F6.7ummJyphot.flux.density;em.IR.4-8umfloatnullablee_F6.7um? Mean error on F6.7ummJystat.errorfloatnullableF14.3um? ISOCAM infrared flux at 14.3ummJyphot.flux.density;em.IR.8-15umfloatnullablee_F14.3um? Mean error on F14.3ummJystat.errorfloatnullable