J/ApJ/670/379ivo://CDS.VizieR/J/ApJ/670/379doi:10.26093/cds/vizier.16700379CDSDieball A.Knigge C.Zurek D.R.Shara M.M.Long K.S.Charles P.A.,Hannikainen D.2010-04-17T18:00:51Z2010-03-26T13:16:18ZCDS support team

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

cds-question@unistra.frglobular-star-clustersultraviolet-astronomyinfrared-photometryvisible-astronomybroad-band-photometryWe have obtained deep FUV and NUV images of the inner region of the dense globular cluster M15 with the HST ACS. The FUV-NUV color-magnitude diagram shows a well-defined track of horizontal branch stars, as well as a trail of blue stragglers and white dwarfs. The main-sequence turnoff is clearly visible at FUV~22.5mag and FUV-NUV~3mag, and the main-sequence stars form a prominent track that extends at least 2mag below the main-sequence turnoff. As such, this is the deepest FUV-NUV color-magnitude diagram of a globular cluster presented so far. Cataclysmic variable and blue straggler candidates are the most centrally concentrated stellar populations, which might either be an effect of mass segregation or reflect the preferred birthplace in the dense cluster core of such dynamically formed objects. We find 41 FUV sources that exhibit significant variability. We classify the variables based on an analysis of their UV colors and variability properties. We find four previously known RR Lyrae and 13 further RR Lyrae candidates, one known Cepheid and six further candidates, six cataclysmic variable candidates, one known and one probable SX Phoenicis star, and the well-known low-mass X-ray binary AC 211. Our analysis represents the first detection of SX Phoenicis pulsations in the FUV. We find that Cepheids, RR Lyrae stars, and SX Phoenicis exhibit massive variability amplitudes in this wave band (several magnitudes).2007ApJ...670..379Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/670/379CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/124/3255 : UBV photometry in M15 (van der Marel+, 2002)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/670/379https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/670/379http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/670/379https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/670/379https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/670/379http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/670/379GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/670/379/table2 (Catalog of all sources in our FUV field of view)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/670/379/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/670/379/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/670/379/table2?GETtext/xml+votable180.050000true322.4979958312.164264440.0055555555555555566/12405https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/670/379?format=asciiUVOpticalInfrareddefaultJ/ApJ/670/379/table2Catalog of all sources in our FUV field of viewrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[DKZ2007]Running identification numbermeta.id;meta.mainintXpixThe X pixel coordinatepixpos.cartesian.xdoubleYpixThe Y pixel coordinatepixpos.cartesian.ydoubleFUVmagACS far-UV magnitude in F140LP filtermagphot.mag;em.UV.100-200nmfloate_FUVmagError in FUVmagmagstat.error;phot.mag;em.UV.FUVfloatFUV-NUV? ACS (FUV-NUV) color (F140LP-F220W) (1)magphot.color;em.UVfloatnullablee_FUV-NUV? Error in FUV-NUV (1)magstat.errorfloatnullableTol? Matching radius between NUV and transformed FUV cartesian coordinates (1)pixpos.angDistancefloatnullableRadRadius from the cluster center (2)arcsecpos.angDistancefloatVmag? V magnitude from Van der Marel et al. (2002, Cat. <J/AJ/124/3255>) (1)magphot.mag;em.opt.VfloatnullableBmag? B magnitude from Van der Marel et al. (2002, Cat. <J/AJ/124/3255>) (1)magphot.mag;em.opt.BfloatnullableUmag? U magnitude from Van der Marel et al. (2002, Cat. <J/AJ/124/3255>) (1)magphot.mag;em.opt.UfloatnullableVdM? Identification form Van der Marel et al. (2002, Cat. <J/AJ/124/3255>) (1)meta.idintnullableVarVariable source identification, VNNmeta.idcharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.main