J/MNRAS/521/3527ivo://CDS.VizieR/J/MNRAS/521/3527CDSCharles E.J.E.Collins M.L.M.Rich R.M.Read J.I.Kim S.Y.Ibata R.A.,Martin N.F.Chapman S.C.Balbinot E.Weisz D.R.2026-09-16T07:26:12Z2026-07-27T10:48:53ZCDS support team

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

cds-question@unistra.frdwarf-galaxiesgalaxiesgalaxy-kinematicsspectroscopyphotometryvisible-astronomyAndromeda (And) XXV has previously been reported as a dwarf spheroidal galaxy (dSph) with little-to-no dark matter. However, the uncertainties on this result were significant. In this study, we nearly double the number of member stars and re-derive the kinematics and mass of And XXV. We find that And XXV has a systemic velocity of v_r_ = -107.7 +/- 1.0 km/s and a velocity dispersion of {sigma}_v_ = 3.7^+1.2^_-1.1_ km/s. With this updated velocity dispersion and a new literature measurement of the radial surface brightness profile, we derive a mass contained within the half-light radius of M(r < r_h_) = 4.79^+3.0^_-2.9_ * 10^6^ M_{sun}_. This mass corresponds to a mass-to-light ratio of [M/L]_rh_ = 25^+17^_-16_ M_{sun}_/L_{sun}_, demonstrating that And XXV is most-likely dark matter dominated. We also measure the metallicity of And XXV to be [Fe/H] = -1.9 +/- 0.1 dex, which is in agreement with previous results. Finally, we extend the analysis of And XXV to include mass modelling using GravSphere. We find that And XXV has a low central dark matter density, {rho}_DM_(150 pc) = 2.3^+1.4^_-1.1_ * 10^7^ M_{sun}_ kpc^-3^, which makes And XXV a clear outlier when compared to other local group dSphs of the similar stellar mass. In a companion paper, we will explore whether some combination of dark matter cusp-core transformations and/or tides can explain And XXV's low density.2023MNRAS.521.3527Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/521/3527CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/491/3496 : Andromeda XIX member stars (Collins+, 2020)J/MNRAS/488/2743 : Giant Galactic dwarf satellite in Gaia DR2 (Torrealba+,2019)J/MNRAS/485/2010 : Kinematics of the Tucana Dwarf Galaxy (Gregory+, 2019)J/MNRAS/380/281 : Faint galactic satellites spectroscopic surveyJ/ApJ/895/78 : [Fe/H] and [{alpha}/Fe] in M31 dwarf galaxies (Wojno+, 2020)J/ApJ/883/11 : Magellan/IMACS spectra of Crater II & Hercules (Fu+, 2019)J/ApJ/838/11 : Member stars in the MW satellite Tucana III (Simon+, 2017)J/ApJ/838/83 : Radial velocities, abundances & membership in TriIIJ/ApJ/833/167 : PAndAS view of Andromeda satellites. II. (Martin+, 2016)J/ApJ/808/95 : Spectroscopy of Reticulum II (Simon+, 2015)J/ApJ/798/77 : Metallicity of RGB stars in 6 M31 dwarf galaxies (Ho+, 2015)J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/ApJ/768/172 : Kinematic analysis of red giant in M31 dSphs (Collins+,2013)J/ApJ/752/45 : SPLASH: Stellar spectroscopy of M31 satellitesJ/ApJ/738/186 : HST and DEIMOS measurements of NGC 2419 stars (Ibata+, 2011)J/ApJ/733/46 : Velocity measurements in Segue 1 (Simon+, 2011)I/345 : Gaia DR2 (Gaia Collaboration, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/521/3527https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/521/3527http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/521/3527https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/521/3527https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/521/3527http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/521/3527GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/521/3527/fullkine (The astrometrics, photometry and probability of the full kinematics stars sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/521/3527/fullkine?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/521/3527/fullkine?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/521/3527/fullkine?GETtext/xml+votable180.050000true7.67346.8190.005555555555555556Cone search capability for table J/MNRAS/521/3527/membkine (The astrometrics, photometry and probability of identified Andromeda XXV member stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/521/3527/membkine?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/521/3527/membkine?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/521/3527/membkine?GETtext/xml+votable180.050000true7.515246.8230.0055555555555555566/2767https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/521/3527?format=asciiOpticaldefaultJ/MNRAS/521/3527/fullkineThe astrometrics, photometry and probability of the full kinematics stars sampleRAJ2000Right ascension (J2000) (RA)degpos.eq.ra;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDEJ2000Declination (J2000) (dec)degpos.eq.dec;meta.mainTmemDisplay the associated data in membkine tablemeta.ref.urlintnullableVKinematic velocity (vel)km/sphys.veloc;pos.heliocentric;spectdoublee_VUncertainty of V (vel_err)km/sstat.error;phys.velocfloatVmagApparent magnitude in V optical band (Vmag)magphot.mag;em.opt.VfloatimagApparent magnitude in i optical band (imag)magphot.mag;em.opt.IfloatS/NSignal to noise ratio (S/N)stat.snrfloatPmemMembership probability estimates (P_member)stat.fit.goodnessfloatJ/MNRAS/521/3527/membkineThe astrometrics, photometry and probability of identified Andromeda XXV member starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000) (RA)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (dec)degpos.eq.dec;meta.mainVKinematic velocity (vel)km/sphys.veloc;pos.heliocentric;spectdoublee_VUncertainty of V (vel_err)km/sstat.error;phys.velocfloatVmagApparent magnitude in V optical band (Vmag)magphot.mag;em.opt.VfloatimagApparent magnitude in i optical band (imag)magphot.mag;em.opt.IfloatS/NSignal to noise ratio (S/N)stat.snrfloatPmemMembership probability estimates (P_member)stat.fit.goodnessfloat