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2012ApJ...758L...5H
Dark Satellites and the Morphology of Dwarf Galaxies
Helmi, Amina ( Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands ); Sales, L. V. ( Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching, Germany ); Starkenburg, E. ( Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands; Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2, Canada ); Starkenburg, T. K. ( Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands ); Vera-Ciro, C. A. ( Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands ); De Lucia, G. ( INAF-Astronomical Observatory of Trieste, via G.B. Tiepolo 11, I-34143 Trieste, Italy ); Li, Y. -S. ( Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China ) show affiliations
The Astrophysical Journal Letters, Volume 758, Issue 1, article id. L5, 5 pp. (2012).
Published in Oct 2012
One of the strongest predictions of the ΛCDM cosmological model is the presence of dark satellites orbiting all types of galaxies. We focus here on the dynamical effects of such satellites on disky dwarf galaxies, and demonstrate that these encounters can be dramatic. Although mergers with M sat > Md are not very common, because of the lower baryonic content they occur much more frequently on the dwarf scale than for L * galaxies. As an example, we present a numerical simulation of a 20% (virial) mass ratio merger between a dark satellite and a disky dwarf (akin to the Fornax dwarf galaxy in luminosity) that shows that the merger remnant has a spheroidal morphology. Perturbations by dark satellites thus provide a plausible path for the formation of dSph systems. The transition from disky to the often amorphous, irregular, or spheroidal morphologies of dwarfs could be a natural consequence of the dynamical heating of hitherto unobservable dark satellites.
Keywords:
Free Keywords: Astrophysics - Cosmology and Extragalactic Astrophysics; Astrophysics - Galaxy Astrophysics; dark matter; galaxies: dwarf; galaxies: evolution; galaxies: interactions
Astronomy: dark matter; galaxies: dwarf; galaxies: evolution; galaxies: interactions
arXiv: Astrophysics - Cosmology and Extragalactic Astrophysics; Astrophysics - Galaxy Astrophysics
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