J/ApJ/756/121ivo://CDS.VizieR/J/ApJ/756/121doi:10.26093/cds/vizier.17560121CDSMusella I.Ripepi V.Marconi M.Clementini G.Dall'Ora M.,Scowcroft V.Moretti M.I.Di Fabrizio L.Greco C.Coppola G.,Bersier D.Catelan M.Grado A.Limatola L.Smith H.A.Kinemuchi K.2014-06-05T14:56:02Z2014-05-12T14:32:48ZCDS support team

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

cds-question@unistra.frvisible-astronomybroad-band-photometryvariable-starsgalaxiesWe present the first time-series study of the ultra-faint dwarf galaxy Hercules. Using a variety of telescope/instrument facilities we secured about 50 V and 80 B epochs. These data allowed us to detect and characterize 10 pulsating variable stars in Hercules. Our final sample includes six fundamental-mode (ab-type) and three first-overtone (c-type) RR Lyrae stars, and one Anomalous Cepheid. The average period of the ab-type RR Lyrae stars, <P_ab_>=0.68days ({sigma}=0.03days), places Hercules in the Oosterhoff II group, as found for almost the totality of the ultra-faint dwarf galaxies investigated so far for variability. The RR Lyrae stars were used to obtain independent estimates of the metallicity, reddening, and distance to Hercules, for which we find [Fe/H]=-2.30+/-0.15dex, E(B-V)=0.09+/-0.02mag, and (m-M)_0_=20.6+/-0.1mag, in good agreement with the literature values. We have obtained a V, B-V color-magnitude diagram (CMD) of Hercules that reaches V~25mag and extends beyond the galaxy's half-light radius over a total area of 40'x36'. The CMD and the RR Lyrae stars indicate the presence of a population as old and metal-poor as (at least) the Galactic globular cluster M68.2012ApJ...756..121Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/756/121CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/752/42 : BV time series in Ursa Major II - Pap. VI (Dall'Ora+, 2012)J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)J/A+A/532/A104 : Hubble flow around Fornax cluster of gal. (Nasonova+, 2011)J/ApJ/704/898 : Photometry of the Hercules dwarf galaxy (Sand+, 2009)J/ApJ/674/L81 : Variable stars in dwarf galaxy CVn I - Pap. II (Kuehn+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/756/121https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/756/121http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/756/121https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/756/121https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/756/121http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/756/121GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/756/121/table2 (Identification and properties of variable stars in the Hercules UFD (Ultra-Faint Dwarf spheroidal))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/756/121/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/756/121/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/756/121/table2?GETtext/xml+votable180.050000true247.759041712.79269440.0055555555555555566/316923.322582951404819e-19 4.920466254354166e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/756/121?format=asciiOpticaldefaultJ/ApJ/756/121/table2Identification and properties of variable stars in the Hercules UFD (Ultra-Faint Dwarf spheroidal)LCLight curve Plotmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDVariable star identification (VNN) (1)meta.id;meta.maincharf_ID[c] c: this star has very scattered light curvesmeta.codecharRAJ2000[16] Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000[12] Degree of declination (J2000)pos.eq.dec;meta.mainTypeVariable type (AC=Anomalous Cepheid)src.classcharNphNumber of photometry measurements (and link to table 3)meta.numberintnullablePer[0.3/0.8] Perioddtime.perioddoubleT0Time of maximum light (HJD-2450000)dtime.epochdouble<Vmag>[20.72/21.35] Mean V-band magnitudemagphot.mag;em.opt.Vfloat<Bmag>[21.14/21.76] Mean B-band magnitudemagphot.mag;em.opt.BfloatAv[0.4/1.2] V-band extinctionmagphys.absorption;em.opt.VfloatAb[0.5/1.4] B-band extinctionmagphys.absorption;em.opt.BfloatJ/ApJ/756/121/table3B, V photometry of the variable stars detectedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDVariable star namemeta.id;meta.maincharTypeVariable classification (AC=Anomalous Cepheid)src.classcharHJD-V? Heliocentric Julian Day of V band observation (HJD-2454211)dtime.epoch;obsdoublenullableVmag[20.43/21.84]? The V band magnitudemagphot.mag;em.opt.Vfloatnullablee_Vmag[0.01/0.2]? The 1{sigma} error in Vmagmagstat.error;phot.mag;em.opt.VfloatnullableHJD-BHeliocentric Julian Day of B band observation (HJD-2454211)dtime.epoch;obsdoubleBmag[20.81/22.37] The B band magnitudemagphot.mag;em.opt.Bfloate_Bmag[0.01/0.2] The 1{sigma} error in Bmagmagstat.error;phot.mag;em.opt.Bfloat