Journal Article

Survival of substructure within dark matter haloes

Giuseppe Tormen, Antonaldo Diaferio and D. Syer

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 299, issue 3, pages 728-742
Published in print September 1998 | ISSN: 0035-8711
Published online September 1998 | e-ISSN: 1365-2966 | DOI:
Survival of substructure within dark matter haloes

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Using high-resolution cosmological N-body simulations, we investigate the survival of dark matter satellites falling into larger haloes. Satellites preserve their identity for some time after merging. We compute their loss of mass, energy and angular momentum as they are dissolved by dynamical friction, tidal forces and collisions with other satellites. We also analyse the evolution of their internal structure. Satellites with less than a few per cent of the mass of the main halo may survive for several billion years, whereas larger satellites rapidly sink into the centre of the main halo potential well and lose their identity. Penetrating encounters between satellites are frequent and may lead to significant mass loss and disruption. Only a minor fraction of cluster mass (10–15 per cent on average) is bound to substructure at most redshifts of interest. We discuss the application of these results to the survival and extent of dark matter haloes associated with galaxies in clusters, and to their interactions. We find that a minor fraction of galaxy-size dark matter haloes are disrupted by redshift z = 0. The fraction of satellites undergoing close encounters is similar to the observed fraction of interacting or merging galaxies in clusters at moderate redshift.

Keywords: methods: numerical; galaxies: clusters: general; galaxies: haloes; galaxies: interactions; cosmology: theory; dark matter

Journal Article.  0 words. 

Subjects: Astronomy and Astrophysics

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