Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dissipationless Mergers of Elliptical Galaxies and the Evolution of the
  Fundamental Plane   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 NFW versus adiabatically contracted NFW), 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.

12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics