Tidal Dwarf Galaxies Bonn 2009: Ghosts from structure formation

Physics Centre Bad Honnef (Germany), May 25-29, 2009

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Poster

Title: Setting an upper limit to the BH in the Ursa Minor dwarf galaxy

Poster file: poster_Brinkmann.pdf

Abstract:

The well-established correlations between the mass of massive black holes (BHs) in the nucleus of most studied galaxies and various global properties of their hosting galaxy lend support to the idea that dwarf galaxies and globular clusters could also host a BH in their centers.

Direct kinematic detection of BHs in dwarf spheroidal (dSph) galaxies are seriously hindered by the small number of stars inside the BH gravitational influence region. The aim of this poster is to establish an upper dynamical limit on the mass of the putative BH in the Ursa Minor (UMi) dSph galaxy.

We present direct N-body simulations of the tidal disruption of the dynamical fossil observed in UMi, with and without BH. This substructure is incompatible with the presence of a massive BH of (2 - 3) 10⁴ M_⊙ within the core of UMi. This upper limit is consistent with the extrapolation of the MBH - sigma relation to the MBH < 10⁶ M_⊙ regime. We also show that the BH may be off-center with respect to the center of symmetry of the whole galaxy.

photos by Julia T. Scho (ForeignLight.com) / Marcel S. Pawlowski