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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 710135.0, MPI für Astronomie / Publikationen_mpia
Spectroscopy of the three distant Andromedan satellites Cassiopeia III, Lacerta I, and Perseus I
Authors:Martin, N. F.; Chambers, K. C.; Collins, M. L. M.; Ibata, R. A.; Rich, R. M.; Bell, E. F.; Bernard, E. J.; Ferguson, A. M. N.; Flewelling, H.; Kaiser, N.; Magnier, E. A.; Tonry, J. L.; Wainscoat, R. J.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:The Astrophysical Journal Letters
Issue / Number:1
Start Page:id. L14 (5 pp)
Audience:Not Specified
Abstract / Description:We present Keck II/DEIMOS spectroscopy of the three distant dwarf galaxies of M31 Lacerta I, Cassiopeia III, and Perseus I, recently discovered within the Pan-STARRS1 3pi imaging survey. The systemic velocities of the three systems (v r, helio = -198.4 ± 1.1 km s-1, -371.6 ± 0.7 km s-1, and -326 ± 3 km s-1, respectively) confirm that they are satellites of M31. In the case of Lacerta I and Cassiopeia III, the high quality of the data obtained for 126 and 212 member stars, respectively, yields reliable constraints on their global velocity dispersions (sigmavr = 10.3 ± 0.9 km s-1 and 8.4 ± 0.6 km s-1, respectively), leading to dynamical-mass estimates for both of ~4 × 107 M &sun; within their half-light radius. These translate to V-band mass-to-light ratios of 15^{+12}_{-9} and 8^{+9}_{-5} in solar units. We also use our spectroscopic data to determine the average metallicity of the three dwarf galaxies ([Fe/H] = -2.0 ± 0.1, -1.7 ± 0.1, and -2.0 ± 0.2, respectively). All these properties are typical of dwarf galaxy satellites of Andromeda with their luminosity and size.
Free Keywords:galaxies: individual: Cas III Lac I Per I; galaxies: kinematics and dynamics; Local Group
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-637X %R 10.1088/2041-8205/793/1/L14
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