Smooth, undisturbed dwarf spheroidal galaxies in the Perseus Cluster core: Implications for dark matter content

Abstract

Using deep HST/ACS observations of the core of the Perseus Cluster, we identify a large population of dwarf elliptical galaxies down to M_V = -12. All these dwarfs are remarkably smooth in appearance, showing no evidence for internal features that could be the result of tidal processes or star formation induced by the cluster potential. Based on these observations and the relatively large sizes of these dwarfs, we argue that at least some must have a large dark matter component to prevent their disruption by the cluster potential. We further derive a new method to quantify the dark matter content of cluster dSphs without the use of kinematics, which are impossible to obtain at these distances. We find that mass-to-light ratios for dwarfs in the core of the Perseus Cluster are comparable to those found for Local Group dSphs, ranging between M/L ~ 1 and 120. This is evidence that dwarf spheroidals reside in dark matter subhalos that protect them from tidal processes in the cores of dense clusters.

4 pages, 3 figures, to be published in Astronomische Nachrichten (proceedings of Symposium 6 of JENAM 2008, Vienna)

References in corpus (4)

• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• Redefining the Missing Satellites Problem
• Keck spectroscopy of the faint dwarf elliptical galaxy population in the Perseus Cluster core: mixed stellar populations and a flat luminosity function
• Hubble Space Telescope survey of the Perseus Cluster - I: The structure and dark matter content of cluster dwarf spheroidals

Cited by in corpus (3)

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• Virgo cluster and field dwarf ellipticals in 3D: III. Spatially and temporally resolved stellar populations
• The HI Structure of the Local Volume Dwarf Galaxy Pisces A