J/ApJ/733/46ivo://CDS.VizieR/J/ApJ/733/46doi:10.26093/cds/vizier.17330046CDSSimon J.D.Geha M.Minor Q.E.Martinez G.D.Kirby E.N.Bullock J.S.,Kaplinghat M.Strigari L.E.Willman B.Choi P.I.Tollerud E.J.Wolf J.2018-01-05T08:57:03Z2012-12-07T13:16:42ZCDS support team

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

cds-question@unistra.frgalaxiesradial-velocityline-intensitiesvisible-astronomysloan-photometryspectroscopyWe present the results of a comprehensive Keck/DEIMOS spectroscopic survey of the ultra-faint Milky Way satellite galaxy Segue 1. We have obtained velocity measurements for 98.2% of the stars within 67pc (10', or 2.3 half-light radii) of the center of Segue 1 that have colors and magnitudes consistent with membership, down to a magnitude limit of r=21.7. Based on photometric, kinematic, and metallicity information, we identify 71 stars as probable Segue 1 members, including some as far out as 87pc. After correcting for the influence of binary stars using repeated velocity measurements, we determine a velocity dispersion of 3.7^+1.4^_-1.1_km/s. The mass within the half-light radius is 5.8^+8.2^_-3.1_x10^5^M_{sun}_. The stellar kinematics of Segue 1 require very high mass-to-light ratios unless the system is far from dynamical equilibrium, even if the period distribution of unresolved binary stars is skewed toward implausibly short periods. With a total luminosity less than that of a single bright red giant and a V-band mass-to-light ratio of 3400M_{sun}_/L_{sun}_, Segue 1 is the darkest galaxy currently known.2011ApJ...733...46Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/733/46CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/306 : The SDSS Photometric Catalog, Release 8 (Adelman-McCarthy+, 2011)J/ApJ/723/1632 : Abundance spreads in Bootes I and Segue 1 (Norris+, 2010)J/ApJ/692/1464 : Spectroscopy of Segue 1 (Geha+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/733/46https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/733/46http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/733/46https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/733/46https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/733/46http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/733/46GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/733/46/table3 (Velocity measurements in Segue 1)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/733/46/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/733/46/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/733/46/table3?GETtext/xml+votable180.050000true151.5582515.91002780.0055555555555555566/4418 4419https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/733/46?format=asciiOpticaldefaultJ/ApJ/733/46/table3Velocity measurements in Segue 1SimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS-DR5 identification (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharVel[-180.2/394.9] Heliocentric velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_Vel[2.2/37.8] Uncertainty in Velkm/sstat.errorfloatEWWeighted sum of CaT line equivalent widths (1)0.1nmspect.line.eqWidthfloate_EW? Uncertainty in EW (1)0.1nmstat.error;spect.line.eqWidthfloatnullableRad[0/17.8] Radial distance from Segue 1arcminphys.angSizefloatMJD[54416.5/55240.5] Modified Julian Date of observationdtime.epochdoublegmag? SDSS-DR5 g band magnitudemagphot.mag;em.opt.Bfloatnullablermag? SDSS-DR5 r band magnitudemagphot.mag;em.opt.Rfloatnullableimag[13.22/22]? SDSS-DR5 i band magnitudemagphot.mag;em.opt.IfloatnullableMm[0/1]? Member status (0=no, 1=member) (2)meta.code.memberintnullableEMpr[0/1]? Member probability from the EM (Expectation Maximization) algorithm (3)meta.id.parent;stat.probabilityfloatnullableBpr[0/1]? Bayesian member probability (4)meta.id.parent;stat.probabilityfloatnullableG09Cross-match with Geha et al., 2009, Cat. J/ApJ/692/1464 within 2"meta.ref.urlintnullableDR7+8Display the SDSS-DR7 and -DR8 data within 2"meta.ref.urlcharSloanDisplay the SDSS online data for this starmeta.ref.urlchar_RAPositions from SDSS-DR5 names (right ascension part)degpos.eq.ra;meta.main_DEPositions from SDSS-DR5 names (declination part)degpos.eq.dec;meta.main