J/ApJ/861/23ivo://CDS.VizieR/J/ApJ/861/23doi:10.26093/cds/vizier.18610023CDSJoo S.-J.Kyeong J.Yang S.-C.Han S.-I.Sung E.-C.Kim D.Jeong H.,Ree C.H.Rey S.-C.Jerjen H.Kim H.-S.Cha S.-M.Lee Y.2020-07-01T08:39:16Z2019-08-05T09:08:58ZCDS support team

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

cds-question@unistra.frgalaxiesphotometryvariable-starsvisible-astronomybroad-band-photometryWe report the detection of RR Lyrae variable stars in Crater II, a recently discovered large and diffuse satellite dwarf galaxy of the Milky Way (MW). Based on B, V time-series photometry obtained with the Korea Microlensing Telescope Network 1.6m telescope at Cerro Tololo Inter-American Observatory, we identified 83 ab-type and 13 c-type pulsators by fitting template light curves. The detected RR Lyrae stars are centrally concentrated, which ensures that most of them are members of Crater II. In terms of the distribution of RRab stars in the period-amplitude diagram, Crater II is clearly different from ultra-faint dwarf (UFD) galaxies, but very similar to the two classical MW dwarf spheroidal (dSph) galaxies Draco and Carina with Oosterhoff-intermediate (Oo-int) properties. Combined with the mean period of ab-type variables (<P_ab_>=0.631+/-0.004days) and the c-type fraction (~0.14) in Crater II, this suggests an Oo-int classification for Crater II and implies that its nature is more like a dSph rather than a UFD. We also estimated the mean metallicity, reddening, and distance of Crater II, from the photometric and pulsation properties of the RR Lyrae stars. The stellar population model we have constructed indicates that Crater II is dominated by an old population, but is relatively younger than the oldest globular clusters in the MW. With a lack of high-amplitude short-period RRab stars, Crater II, like most of the other less massive dSphs, is probably not a surviving counterpart of the major building blocks of the MW halo.2018ApJ...861...23Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/861/23CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/315 : UCAC3 Catalogue (Zacharias+ 2009)II/350 : VLT Survey Telescope ATLAS (Shanks+, 2015)J/AJ/115/193 : RR Lyrae V light curves (Layden, 1998)J/AJ/115/1856 : Dwarf Cepheids in Carina (Mateo+, 1998)J/AJ/119/1760 : M54 and Sgr dSph VI photometry (Layden+, 2000)J/AJ/124/1464 : Variable stars in Andromeda VI (Pritzl+, 2002)J/AJ/129/267 : RR Lyrae variables in NGC 5272 (Cacciari+, 2005)J/AJ/130/873 : BQS objects in the SDSS DR3 area (Jester+, 2005)J/AJ/132/1361 : RR Lyrae variables in M33 (Sarajedini+, 2006)J/MNRAS/380/281 : Faint galactic satellites spectrosc. survey (Martin+, 2007)J/AJ/136/1921 : Variable stars of Draco dSph (Kinemuchi+, 2008)J/ApJ/674/L81 : Variable stars in dwarf galaxy CVn I (Kuehn+, 2008)J/AcA/58/293 : Type-II and anomalous Cepheids in LMC (Soszynski+, 2008)J/MNRAS/397/1748 : Spectroscopic study of Segue 2 (Belokurov+, 2009)J/MNRAS/398/1757 : RR Lyraes in SDSS stripe 82 (Watkins+, 2009)J/ApJ/708/560 : Spectroscopy of UMa II and Coma Ber (Frebel+, 2010)J/ApJ/723/1632 : Abundance spreads in Bootes I and Segue 1 (Norris+, 2010)J/ApJ/724/799 : RR Lyrae variables in M33. II. (Yang+, 2010)J/AJ/139/357 : Variable stars in NGC 5286 (Zorotovic+, 2010)J/AJ/141/171 : RR Lyrae stars in M31 ultra-deep fields (Jeffery+, 2011)J/ApJ/733/46 : Velocity measurements in Segue 1 (Simon+, 2011)J/ApJ/756/108 : HST VI phot. of variable stars in Leo T (Clementini+, 2012)J/ApJ/752/42 : BV time series in Ursa Major II (Dall'Ora+, 2012)J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)J/ApJ/756/121 : Variable stars in Her dwarf galaxy (Musella+, 2012)J/ApJ/756/79 : Optical phot. in 3 Local Group dwarf galaxies (Sand+, 2012)J/ApJ/767/62 : RR Lyrae stars BV photometry in UMa I (Garofalo+, 2013)J/ApJ/763/40 : UBVI data of GCs in the Fornax galaxy cluster (Kim+, 2013)J/ApJ/767/134 : Abundances of red giants in UFD galaxies (Vargas+, 2013)J/ApJ/793/135 : Positions and distances of RR Lyrae stars (Sesar+, 2014)J/PASP/126/616 : Variable stars in Leo I dSph (Stetson+, 2014)J/ApJ/784/76 : RR Lyrae in ESO294-G010 and ESO410-G005 (Yang+, 2014)J/ApJ/781/22 : La Silla QUEST RR Lyrae star survey (Zinn+, 2014)J/ApJ/814/71 : Carina project IX: UBVI data of variables (Coppola+, 2015)J/ApJ/803/63 : gr photometry of stars in Kim 2 (Kim+, 2015)J/ApJ/832/99 : HK', CN & CH indexes in NGC 362 & NGC 6723 (Lim+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/861/23https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/861/23http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/861/23https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/861/23https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/861/23http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/861/23GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/861/23/table1 (Pulsation properties of RR Lyrae stars in Crater II)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/861/23/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/861/23/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/861/23/table1?GETtext/xml+votable180.050000true177.195625-18.62471390.0055555555555555565/6295 6/25174 25175 25352https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/861/23?format=asciiOpticaldefaultJ/ApJ/861/23/table1Pulsation properties of RR Lyrae stars in Crater IIrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDVariable identifier (V1 to V97); <[JKY2018] NNN> in Simbadmeta.id;meta.maincharRAJ2000[11] Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000[17/19] Degree of declination (J2000)pos.eq.dec;meta.mainTypeRR Lyrae type ("ab": 83 occurrences, "c": 13 occurrences or "ab?": 1 occurrence)meta.note;src.morph.typecharPer[0.2/0.8] Perioddtime.periodfloatEpochEpoch max; JD-2457000dtime.epoch;stat.maxdoubleBmean[20.9/21.7] Intensity-weighted mean B-band magnitudemagphot.mag;em.opt.BfloatVmean[20.5/21.4] Intensity-weighted mean V-band magnitudemagphot.mag;em.opt.VfloatNB[36/142] Number of observations used in our light curve analysis in B-bandmeta.numberintNV[36/145] Number of observations used in our light curve analysis in V-bandmeta.numberintBamp[0.2/1.5] Pulsation amplitude in B-bandmagphot.mag;em.opt.BfloatVamp[0.2/1.1] Pulsation amplitude in V-bandmagphot.mag;em.opt.VfloatNoteNote(s)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlchar