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arXiv · astro-ph/0109492

The Extended Shapes of Galactic Satellites

S. R. Majewski·A. D. Forestell·J. C. Ostheimer·C. Palma·M. H. Siegel·S. Sohn·K. B. Westfall·R. J. Patterson·P. M. Frinchaboy·R. Link
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Abstract

We are exploring the extended stellar distributions of Galactic satellite galaxies and globular clusters. For seven objects studied thus far, the observed profile departs from a King function at large r, revealing a ``break population'' of stars. In our sample, the relative density of the ``break'' correlates to the inferred M/L of these objects. We discuss opposing hypotheses for this trend: (1) Higher M/L objects harbor more extended dark matter halos that support secondary, bound, stellar ``halos''. (2) The extended populations around dwarf spheroidals (and some clusters) consist of unbound, extratidal debris from their parent objects, which are undergoing various degrees of tidal disruption. In this scenario, higher M/L ratios reflect higher degrees of virial non-equilibrium in the parent objects, thus invalidating a precept underlying the use of core radial velocities to obtain masses.

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S. R. Majewski, A. D. Forestell, J. C. Ostheimer, C. Palma, M. H. Siegel, S. Sohn, K. B. Westfall, R. J. Patterson, P. M. Frinchaboy, R. Link. 2001-09-26. The Extended Shapes of Galactic Satellites. https://doi.org/10.1142/9789812778017_0034

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