Dissipationless mergers of elliptical galaxies and the evolution of the fundamental plane

Michael Boylan-Kolchin, Chung Pei Ma, Eliot Quataert

Research output: Contribution to journalArticlepeer-review

104 Scopus citations

Abstract

We carry out numerical simulations of dissipationless major mergers of elliptical galaxies using initial galaxy models that consist of a dark matter halo and a stellar bulge with properties consistent with the observed fundamental plane. By varying the density profile of the dark matter halo [standard Navarro, Frenk & White (NFW) profile versus adiabatically contracted NFW profile], the global stellar to dark matter mass ratio and the orbit of the merging galaxies, we are able to assess the impact of each of these factors on the structure of the merger remnant. Our results indicate that the properties of the remnant bulge depend primarily on the angular momentum and energy of the orbit; for a cosmologically motivated orbit, the effective radius and velocity dispersion of the remnant bulge remain approximately on the fundamental plane. This indicates that the observed properties of elliptical galaxies are consistent with significant growth via late dissipationless mergers. We also find that the dark matter fraction within the effective radius of our remnants increases after the merger, consistent with the hypothesis that the tilt of the fundamental plane from the virial theorem is due to a varying dark matter fraction as a function of galaxy mass.

Original languageEnglish (US)
Pages (from-to)184-196
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume362
Issue number1
DOIs
StatePublished - Sep 1 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Dark matter
  • Galaxies: evolution
  • Galaxies: fundamental parameters
  • Galaxies: structure
  • Methods: N-body simulations

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