J/MNRAS/449/3651ivo://CDS.VizieR/J/MNRAS/449/3651doi:10.26093/cds/vizier.74493651CDSMarocco F.Jones H.R.A.Day-Jones A.C.Pinfield D.J.Lucas P.W.,Burningham B.Zhang Z.H.Smart R.L.Gomes J.I.Smith L.2024-08-14T20:21:17Z2016-01-21T15:39:32ZCDS support team

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

cds-question@unistra.frlate-type-starsdwarf-starsinfrared-photometryline-intensitiesWe present the spectroscopic analysis of a large sample of late-M, L, and T dwarfs from the United Kingdom Deep Infrared Sky Survey. Using the YJHK photometry from the Large Area Survey and the red-optical photometry from the Sloan Digital Sky Survey we selected a sample of 262 brown dwarf candidates and we have followed-up 196 of them using the echelle spectrograph X-shooter on the Very Large Telescope. The large wavelength coverage (0.30-2.48um) and moderate resolution (R~5000-9000) of X-shooter allowed us to identify peculiar objects including 22 blue L dwarfs, 2 blue T dwarfs, and 2 low-gravity M dwarfs. Using a spectral indices-based technique, we identified 27 unresolved binary candidates, for which we have determined the spectral type of the potential components via spectral deconvolution. The spectra allowed us to measure the equivalent width of the prominent absorption features and to compare them to atmospheric models. Cross-correlating the spectra with a radial velocity standard, we measured the radial velocity of our targets, and we determined the distribution of the sample, which is centred at -1.7+/-1.2km/s with a dispersion of 31.5km/s. Using our results, we estimated the space density of field brown dwarfs and compared it with the results of numerical simulations. Depending on the binary fraction, we found that there are (0.85+/-0.55)x10^-3^ to (1.00+/-0.64)x10^-3^ objects per cubic parsec in the L4-L6.5 range, (0.73+/-0.47)x10^-3^ to (0.85+/-0.55)x10^-3^ objects per cubic parsec in the L7-T0.5 range, and (0.74+/-0.48)x10^-3^ to (0.88+/-0.56)x10^-3^ objects per cubic parsec in the T1-T4.5 range. We notice that there seems to be an excess of objects in the L-T transition with respect to the late-T dwarfs, a discrepancy that could be explained assuming a higher binary fraction than expected for the L-T transition, or that objects in the high-mass end and low-mass end of this regime form in different environments, i.e. following different initial mass functions.2015MNRAS.449.3651Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/449/3651CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/430/1171 : Sub-stellar birth rate from UKIDSS (Day-Jones+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/449/3651https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/449/3651http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/449/3651https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/449/3651https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/449/3651http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/449/3651GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/449/3651/table1 (The objects observed)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/449/3651/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/449/3651/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/449/3651/table1?GETtext/xml+votable180.050000true1.555166715.67241670.0055555555555555566/22 48 56 64-66 550 4119 4129 4141 4147 4166 4181 4203 4237 4240 4755 4761 8210 8223 8225 8234 8261 8269 8292 8329 8344 8377 8379 8448 8713 8717 17663 17746 17757 17811 17826 17901 17997 18024 18065 18084 18092 18178 18225 18229 18245 18300 18303 18312 18383 18387-18389 18409 18411 18686 18770 18792-18793 18797 18837 18844 18853 18858 18860 18862 18881 18933 19021 19047 19052 19200 19247 19253 19268-19270 19273 19278 19280 19515 19583 19596 19678 19727 19733 19747 19752 19754-19755 19761 19988 19996 20000 21831 21835 21847 21851 21874 21877 21982 23269-23270 23273 23278 25590 25853 25943 25945 25965 25971 26017 26036 26050 26072 26183 26196 26269 26278 26346 26379 26402 26445 26448 26451 26465 26470 26477 26551 26560 26861 26871 26959 26980 26984 26987 27218 27225 27251 27269 27271 27288 27293 27303 27313 27336 27340 27382-27384 27386 27480 27493 27531 27552 27561 27568 27580 27677 27701 27717 27752 27754 27772 27797 27800 27802 27816 27852 27860 27868 27912 27915-27916 27936 27970 31370 31376 31381 31393 31403 31411 31419 31458 31486 40949 40953 450531.3088508223161842e-20 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/449/3651?format=asciiInfrareddefaultJ/MNRAS/449/3651/table1The objects observede_Ymagrms uncertainty on Ymagmagstat.error;phot.mag;em.opt.BfloatJmagUKIDSS LAS DR7 J magnitudemagphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.mag;em.IR.JfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintULASULAS name (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharBRLTBRLT sequential numbermeta.recordintYmagUKIDSS LAS DR7 Y magnitudemagphot.mag;em.IR.JfloatHmagUKIDSS LAS DR7 H magnitudemagphot.mag;em.IR.Hfloate_Hmagrms uncertainty on Hmagmagstat.error;phot.mag;em.IR.HfloatKmag? UKIDSS LAS DR7 K magnitudemagphot.mag;em.IR.Kfloatnullablee_Kmag? rms uncertainty on Ymagmagstat.error;phot.mag;em.IR.Kfloatnullableimag? SDSS DR7 i magnitudemagphot.mag;em.opt.Ifloatnullablee_imag? rms uncertainty on imagmagstat.error;phot.mag;em.opt.Ifloatnullablezmag? SDSS DR7 z magnitudemagphot.mag;em.opt.Ifloatnullablee_zmag? rms uncertainty on zmagmagstat.error;phot.mag;em.opt.IfloatnullableSpTypeMK spectral type derived in Section 3.1src.spTypechare_SpTyperms uncertainty on SpTypestat.error;src.spTypefloatRefDiscovery reference (1)meta.ref;pos.framecharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from ULAS name (right ascension part)degpos.eq.ra;meta.main_DEPositions from ULAS name (declination part)degpos.eq.dec;meta.mainJ/MNRAS/449/3651/table5Spectral indices for the objects in the sampleCH4-JCH_4_-J spectral index (1)spect.indexfloatCH4-HCH_4_-H spectral index (1)spect.indexfloatBRLTBRLT sequential numbermeta.recordintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpTypeMK spectral typesrc.spTypechare_SpTyperms uncertainty on SpTypestat.error;src.spTypefloatH2O-JH_2_O-J spectral index (1)spect.indexfloatH2O-HH_2_O-H spectral index (1)spect.indexfloatH2O-KH_2_O-K spectral index (1)spect.indexfloatCH4-KCH_4_-K spectral index (1)spect.indexfloatK/JK/J spectral index (1)spect.indexfloatH-dipH-dip spectral index (1)spect.indexfloatJ/MNRAS/449/3651/table6The equivalent width obtained from the spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBRLTBRLT sequential numbermeta.recordintSpTypeMK spectral typesrc.spTypechare_SpTyperms uncertainty on SpTypestat.error;src.spTypefloatEWNaI? NaI (1.139um) equivalent width (1)0.1nmspect.line.eqWidthfloatnullableu_EWNaI[i] i: measurements with relative errors larger than 0.33meta.code.errorcharEWKI1? KI (1.169um) equivalent width (1)0.1nmspect.line.eqWidthfloatnullableu_EWKI1[i] i: measurements with relative errors larger than 0.33meta.code.errorcharEWKI2? KI (1.177um) equivalent width (1)0.1nmspect.line.eqWidthfloatnullableu_EWKI2[i] i: measurements with relative errors larger than 0.33meta.code.errorcharEWKI3? KI (1.244um) equivalent width (1)0.1nmspect.line.eqWidthfloatnullableu_EWKI3[i] i: measurements with relative errors larger than 0.33meta.code.errorcharEWKI4? KI (1.253um) equivalent width (1)0.1nmspect.line.eqWidthfloatnullableu_EWKI4[i] i: measurements with relative errors larger than 0.33meta.code.errorcharJ/MNRAS/449/3651/tablea1The log of the observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBRLTBRLT sequential numbermeta.recordintObs.dateObservation datetime.epoch;obsnullableStdTelluric standard star namemeta.idcharSpTypeMK spectral type of telluric standard starsrc.spTypecharSpStdSpectrophotometric standard usedmeta.idcharJ/MNRAS/449/3651/tableb1Additional photometry for our targets, obtained from SDSS DR10 and WISE All-Sky Data ReleaserecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBRLTBRLT sequential numbermeta.recordintumag? SDSS u magnitudemagphot.mag;em.opt.Ufloatnullablee_umag? rms uncertainty on umagmagstat.error;phot.mag;em.opt.Ufloatnullablegmag? SDSS g magnitudemagphot.mag;em.opt.Bfloatnullablee_gmag? rms uncertainty on gmagmagstat.error;phot.mag;em.opt.Bfloatnullablermag? SDSS r magnitudemagphot.mag;em.opt.Rfloatnullablee_rmag? rms uncertainty on rmagmagstat.error;phot.mag;em.opt.RfloatnullableW1? WISE W1 magnitudemagphot.mag;em.IR.3-4umfloatnullablee_W1? rms uncertainty on W1magstat.errorfloatnullablel_W2Limit flag on W2meta.code.errorcharW2? WISE W2 magnitudemagphot.mag;em.IR.4-8umfloatnullablee_W2? rms uncertainty on W2magstat.errorfloatnullablel_W3Limit flag on W3meta.code.errorcharW3? WISE W3 magnitudemagphot.flux.density;em.IR.8-15umfloatnullablee_W3? rms uncertainty on W3magstat.errorfloatnullableNote[ab] Note (1)meta.notechar