J/ApJ/916/10ivo://CDS.VizieR/J/ApJ/916/10doi:10.26093/cds/vizier.19160010CDSGarofalo A.Tantalo M.Cusano F.Clementini G.Calura F.Muraveva T.,Paris D.Speziali R.2023-03-20T14:21:24Z2023-01-19T12:57:44ZCDS support team

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

cds-question@unistra.frvisible-astronomyWide-band photometryvariable-starsWe have used B, V time-series photometry collected with the Large Binocular Telescope to undertake the first study of variable stars in the Milky Way ultra-faint dwarf (UFD) satellites Pisces II and PegasusIII. In Pisces II we have identified an RRab star, one confirmed and a candidate SX Phoenicis star, and a variable with uncertain classification. In Pegasus III we confirmed the variability of two sources: an RRab star and a variable with uncertain classification, similar to the case found in Pisces II. Using the intensity-averaged apparent magnitude of the bona fide RRab star in each galaxy, we estimate distance moduli of (m-M)_0_=21.22+/-0.14mag (d=175+/-11kpc) and 21.21+/-0.23mag (d=174+/-18kpc) for Pisces II and Pegasus III, respectively. Tests performed to disentangle the actual nature of variables with an uncertain classification led us to conclude that they most likely are bright, long-period, and very metal-poor RRab members of their respective hosts. This may indicate that Pisces II and Pegasus III contain a dominant old stellar population (t>12Gyr) with metallicity <[Fe/H]>-1.8dex along with, possibly, a minor, more metal-poor component, as supported by the V, B-V color-magnitude diagrams of the two UFDs and their spectroscopically confirmed members. The metallicity spread that we derived from our data sample is >~0.4dex in both systems. Lastly, we built isodensity contour maps that do not reveal any irregular shape, thus making the existence of a physical connection between these UFDs unlikely.2021ApJ...916...10Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/916/10CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/350 : VLT Survey Telescope ATLAS (Shanks+, 2015)I/345 : Gaia DR2 (Gaia Collaboration, 2018)VII/195 : Globular Clusters in the Milky Way (Harris, 1996)VII/202 : Globular Clusters in the Milky Way (Harris, 1997)J/A+A/312/111 : [Fe/H] from RR Lyrae light curves (Jurcsik+, 1996)J/A+A/391/945 : HST phot. of 74 galactic globular clusters (Piotto+, 2002)J/A+A/421/937 : Metal abundances of LMC RR Lyrae (Gratton+, 2004)J/AJ/129/267 : RR Lyrae variables in NGC 5272 (Cacciari+, 2005)J/MNRAS/371/1503 : Synthetic photometry of RR Lyr (Marconi+, 2006)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/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)J/ApJ/710/1664 : BV photometry in Leo IV and Leo V dSphs (de Jong+, 2010)J/ApJ/723/1632 : Abundance spreads in Bootes I and Segue 1 (Norris+, 2010)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/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/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014)J/MNRAS/437/2307 : LMC anomalous Cepheid Ks light curves (Ripepi+, 2014)J/ApJ/793/135 : Positions and distances of RR Lyrae stars (Sesar+, 2014)J/MNRAS/479/5343 : Nearby dwarf galaxy in Magellanic bridge (Koposov+, 2018)J/ApJ/857/145 : MagLiteS Carina II and Carina III spectroscopy (Li+, 2018)J/ApJ/855/43 : Distant RR Lyrae stars discovered with HiTS (Medina+, 2018)J/MNRAS/481/1195 : GaiaDR2 RR Lyrae stars as standard candles (Muraveva+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/916/10https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/916/10http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/916/10https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/916/10https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/916/10http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/916/10GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/916/10/table5 (Properties of the variable stars identified in Psc II and Peg III)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/916/10/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/916/10/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/916/10/table5?GETtext/xml+votable180.050000true344.624408335.953033330.0055555555555555566/18926 192393.322582951404819e-19 4.920466254354166e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/916/10?format=asciiOpticaldefaultJ/ApJ/916/10/table5Properties of the variable stars identified in Psc II and Peg IIIrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalUFD galaxy identifiermeta.id.parentcharVarVariable star identifiermeta.id;meta.maincharn_VarSee Section 7 for the cases of V4 in PscII and V2 in PegIIImeta.notecharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainOTypeObject typesrc.classcharPer[0.049/0.73] Perioddtime.perioddoubleHJD[296.71/357.56]? Heliocentric Julian Date, HJD-2457000dtime.epochdoublenullableBmag[21.98/24.245]? Mean B-band Johnson magnitudemagphot.mag;em.opt.BfloatnullableAb[0.94/1.26]? Extinction in B-bandmagphys.absorptionfloatnullableVmag[21.63/23.935]? Mean V-band Johnson magnitudemagphot.mag;em.opt.VfloatnullableAv[0.69/1.16]? Extinction in V-bandmagphys.absorptionfloatnullable[Fe/H]Metallicitylog(Sun)phys.abund.ZcharNpNumber of photometric measurements for this star (link to Table 5)meta.numberintnullableLCInteractive LC Plotmeta.ref.urlcharJ/ApJ/916/10/table4B and V timeseries photometry of the Psc II and Peg III variable starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalUFD galaxy identifiermeta.id.parentcharVarVariable star identifiermeta.id;meta.maincharHJDB[297.7/358.7] B band observation heliocentric Julian Date; HJDB-2457000dtime.epochdoubleBmag[21.44/24.95] Apparent Johnson B band magnitudemagphot.mag;em.opt.Bfloate_Bmag[0.01/0.3] Uncertainty in Bmagmagstat.error;phot.magfloatHJDV[297.7/358.7]? V band observation heliocentric Julian Date; HJDV-2457000dtime.epochdoublenullableVmag[21.18/24.44]? Apparent Johnson V band magnitudemagphot.mag;em.opt.Vfloatnullablee_Vmag[0.01/0.2]? Uncertainty in Vmagmagstat.error;phot.magfloatnullable