Tollerud, Erik J. and Beaton, Rachael L. and Geha, Marla C. and Bullock, James S. and Guhathakurta, Puragra and Kalirai, Jason S. and Majewski, Steven R. and Kirby, Evan N. and Gilbert, Karoline M. and Yniguez, Basilio and Patterson, Richard J. and Ostheimer, James C. and Cooke, Jeff and Dorman, Claire E. and Choudhury, Abrar and Cooper, Michael C. (2012) The SPLASH Survey: Spectroscopy of 15 M31 Dwarf Spheroidal Satellite Galaxies. Astrophysical Journal, 752 (1). Art. No. 45. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20120716-133219730
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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.
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| Additional Information: | © 2012 American Astronomical Society. Received 2011 December 6; accepted 2012 April 2; published 2012 May 24. We wish to acknowledge Nhung Ho, Greg Martinez, and Ricardo Munoz for helpful discussions, as well as Stacy Mc- Gaugh, Mark Fardal, Alan McConnachie, and the anonymous referee for helpful suggestions regarding the manuscript. E.J.T. acknowledges support from a Graduate Assistance in Areas of National Need (GAANN) Fellowship and a Fletcher Jones Fellowship. R.L.B. acknowledges receipt of the Mark C. Pirrung Family Graduate Fellowship from the Jefferson Scholars Foundation and a Fellowship Enhancement for Outstanding Doctoral Candidates from the Office of the Vice President of Research at the University of Virginia. M.G. acknowledges support from NSF grant AST-0908752 and the Alfred P. Sloan Foundation. P.G., J.S.B., and S.R.M. acknowledge support from collaborative NSF grants AST-1010039, AST-1009973, AST-1009882, and AST-0607726. A.C. thanks the UC Santa Cruz Science Internship Program for support. Additional support for this work was provided by NASA through Hubble Fellowship grants 51256.01 and 51273.01 awarded to E.N.K. and K.M.G. by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. The spec2d pipeline used to reduce the DEIMOS data was developed at UC Berkeley with support from NSF grant AST-0071048. This work made extensive use of code developed for the Astropysics18 and Pymodelfit (Tollerud 2011)19 open-source projects. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Some slitmasks were designed based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona University System; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia. This research used the facilities of the Canadian Astronomy Data Centre operated by the National Research Council of Canada with the support of the Canadian Space Agency. Facilities: Keck:II (DEIMOS),Mayall (Mosaic), LBT (LBC). The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. | ||||||||||||||||||||||||||||||||
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| Subject Keywords: | dark matter; galaxies: dwarf; galaxies: fundamental parameters; galaxies: individual (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); galaxies: kinematics and dynamics; Local Group | ||||||||||||||||||||||||||||||||
| Record Number: | CaltechAUTHORS:20120716-133219730 | ||||||||||||||||||||||||||||||||
| Persistent URL: | http://resolver.caltech.edu/CaltechAUTHORS:20120716-133219730 | ||||||||||||||||||||||||||||||||
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| Official Citation: | The SPLASH Survey: Spectroscopy of 15 M31 Dwarf Spheroidal Satellite Galaxies Erik J. Tollerud et al. 2012 ApJ 752 45 | ||||||||||||||||||||||||||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||||||||||||||||||||||||||||||
| ID Code: | 32478 | ||||||||||||||||||||||||||||||||
| Collection: | CaltechAUTHORS | ||||||||||||||||||||||||||||||||
| Deposited By: | Jason Perez | ||||||||||||||||||||||||||||||||
| Deposited On: | 16 Jul 2012 23:02 | ||||||||||||||||||||||||||||||||
| Last Modified: | 26 Dec 2012 15:33 |
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