J/A+A/534/A10ivo://CDS.VizieR/J/A+A/534/A10doi:10.26093/cds/vizier.35340010CDSAndersen M.Meyer M.R.Robberto M.Bergeron L.E.Reid N.2011-12-27T15:02:58Z2011-10-25T14:23:38ZCDS support team

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

cds-question@unistra.fropen-star-clusterspre-main-sequence-starshst-photometryWe present deep HST/NICMOS Camera 3 F110W and F160W imaging of a 26'x33', corresponding to 3.1x3.8pc^2^, non-contiguous field towards the Orion Nebula Cluster (ONC). The main aim is to determine the ratio of low-mass stars to brown dwarfs for the cluster as a function of radius out to a radial distance of 1.5pc. The sensitivity of the data outside the nebulous central region is F160W<=21.0mag, significantly deeper than previous studies of the region over a comparable area. We create an extinction limited sample and determine the ratio of low-mass stars (0.08-1M_{sun}_) to brown dwarfs (0.02-0.08M_{sun}_ and 0.03-0.08M_{sun}_) for the cluster as a whole and for several annuli. The ratio found for the cluster within a radius of 1.5pc is R_02_=N(0.08-1M_{sun}_)/N(0.02-0.08M_{sun}_)=1.7+/-0.2, and R_03_=N(0.08-1M_{sun}_)/N(0.03-0.08M_{sun}_)=2.4+/-0.2, after correcting for field stars. The ratio for the central 0.3x0.3pc^2^ region down to 0.03M_{sun}_ was previously found to be R_03_=3.3^+0.8^_-0.7_, suggesting the low-mass content of the cluster is mass segregated. We discuss the implications of a gradient in the ratio of stars to brown dwarfs in the ONC in the context of previous measurements of the cluster and for other nearby star forming regions. We further discuss the current evidence for variations in the low-mass IMF and primordial mass segregation.2011A&A...534A..10Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/534/A10CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/120/1426 : Chandra sources in ONC + BN-KL (Garmire+, 2000)J/AJ/121/1676 : ONC low-mass stars photometry (Rebull+, 2001)J/ApJ/660/704 : Optical and X-ray variability of ONC PMS (Stassun+, 2007)J/ApJ/660/1462 : Abundances of ONC X-ray PMS stars (Maggio+, 2007)J/ApJ/671/605 : NGC 2264 and ONC PMS stars in the infrared (Cieza+, 2007)J/ApJ/677/401 : X-ray properties of protostars in ONC (Prisinzano+, 2008)J/ApJS/183/261 : Optical photometry of the ONC (Da Rio+, 2009)J/MNRAS/400/603 : New variables in ONC (Parihar+, 2009)J/A+A/502/883 : ONC very low mass stars I phot. (Rodriguez-Ledesma+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/534/A10https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/534/A10http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/534/A10https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/534/A10https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/534/A10http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/534/A10GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/534/A10/table1 (Sources detected in the NICMOS camera 3 mosaics)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/534/A10/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/534/A10/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/534/A10/table1?GETtext/xml+votable180.050000true83.55908-5.495810.0055555555555555566/21438-21439 22804-228051.1079043399350366e-19 2.1998683494814e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/534/A10?format=asciiOpticaldefaultJ/A+A/534/A10/table1Sources detected in the NICMOS camera 3 mosaicsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[0/2053] Sequential numbermeta.id;meta.mainintn_Seq[*] no astrometric calibration (1)meta.notecharRAJ2000Right ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainF110W? HST/NICMOS F110W magnitude (VEGA system)magphot.mag;em.IR.Jfloatnullablee_F110W? F110W errormagstat.errorfloatnullableF160WHST/NICMOS F160W magnitude (VEGA system)magphot.mag;em.IR.Hfloate_F160WF160W errormagstat.errorfloat