Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/224888

Title

The SPLASH survey: spectroscopy of 15 M31 dwarf spheroidal satellite galaxies

Author(s)

Tollerud, Erik J.;  Beaton, Rachael L.;  Geha, Marla C.;  Bullock, James S.;  Guhathakurta, Puragra;  Kalirai, Jason S.;  Majewski, Steve R.;  Kirby, Evan N.;  Gilbert, Karoline M.;  Yniguez, Basilio;  Patterson, Richard J.;  Ostheimer, James C.;  Cooke, Jeff;  Dorman, Claire E.;  Choudhury, Abrar;  Cooper, Michael C.

Abstract

We present a resolved star spectroscopic survey of 15 dwarf spheroidal (dSph) satellites of the Andromeda galaxy (M31). We filter foreground contamination from Milky Way (MW) stars, noting that MW substructure is evident in this contaminant sample. We also filter M31 halo field giant stars and identify the remainder as probable dSph members. We then use these members to determine the kinematical properties of the dSphs. For the first time, we confirm that And XVIII, XXI, and XXII show kinematics consistent with bound, dark-matter dominated galaxies. From the velocity dispersions for the full sample of dSphs we determine masses, which we combine with the size and luminosity of the galaxies to produce mass size-luminosity scaling relations. With these scalings we determine that the M31 dSphs are fully consistent with the MW dSphs, suggesting that the well-studied MW satellite population provides a fair sample for broader conclusions. We also estimate dark matter halo masses of the satellites and find that there is no sign that the luminosity of these galaxies depends on their dark halo mass, a result consistent with what is seen for MW dwarfs. Two of the M31 dSphs (And XV, XVI) have estimated maximum circular velocities smaller than 12 km s–1 (to 1σ), which likely places them within the lowest-mass dark matter halos known to host stars (along with Boötes I of the MW). Finally, we use the systemic velocities of the M31 satellites to estimate the mass of the M31 halo, obtaining a virial mass consistent with previous results.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Astrophysical Journal, Vol. 752, no. 1 (Jun 2012), article no. 45

Publication year

2012

FOR Code(s)

0201 Astronomical and Space Sciences;  0305 Organic Chemistry;  0306 Physical Chemistry (Incl. Structural)

Keyword(s)

And I;  And III;  And V;  And VII;  And IX;  And X;  And XI;  And XII;  And XIII;  And XIV;  And XV;  And XVI;  And XVIII;  And XXI;  And XXII;  Dark matter;  Dwarf galaxies;  Dynamics;  Fundamental parameters;  Kinematics;  Local Group

Publisher

Institute of Physics Publishing

ISSN

0004-637X

Publisher URL

http://dx.doi.org/10.1088/0004-637x/752/1/45

Copyright

Copyright © 2012 The American Astronomical Society. All rights reserved.

Peer reviewed