On the Formation of Boxy and Disky Elliptical Galaxies
Abstract
N-body simulations of major spiral-spiral mergers with different mass ratios q = M1:M2 <= 4:1 are presented. All mergers lead to spheroidal stellar systems with r1/4-like surface density profiles, resembling elliptical galaxies. The internal dynamical structure of the remnants does however depend critically on the adopted mass ratio. Equal-mass mergers with q <= 2:1 form radially anisotropic, slowly rotating systems with preferentially boxy isophotes. Unequal-mass mergers with q > 2:1 result in the formation of rotationally supported ellipticals with disky isophotes and small minor axis rotation. Projection effects lead in general to a large scatter in the kinematical and isophotal properties. If the observed dichotomy between boxy and disky ellipticals is a result of different mass ratios of the merger components massive ellipticals must have formed preferentially from equal-mass mergers in contrast to low-mass ellipticals which had to form from unequal-mass mergers.
- Publication:
-
Dynamics of Galaxies: from the Early Universe to the Present
- Pub Date:
- 2000
- DOI:
- 10.48550/arXiv.astro-ph/9912489
- arXiv:
- arXiv:astro-ph/9912489
- Bibcode:
- 2000ASPC..197..217B
- Keywords:
-
- ELLIPTICAL GALAXIES;
- GALACTIC EVOLUTION;
- MERGERS;
- NUMERICAL N-BODY SIMULATIONS;
- Astrophysics
- E-Print:
- 4 pages, 1 postscript figure, uses newpasp.sty, to appear in ASP Conf. Proc. "Galaxy Dynamics"