Scaling Relations in Dissipationless Spiral-like Galaxy Mergers

Details Scaling Relations in Dissipationless Spiral-like Galaxy Mergers Scaling Relations in Dissipationless Spiral-like Galaxy Mergers

2009-05-15

arxiv.org/abs/0905.2475v1

Astrophys.J.698:2023-2030,2009

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

8 pages and 2 figures. Accepted for publication in ApJ

Scientific paper

10.1088/0004-637X/698/2/2023

We determine both representations of the Fundamental Plane [Re Sig^a Ie^b and Re (Sig^2/Ie)^lambda] and the luminosity-effective phase space density [L fe^(-gamma)] scaling relation for N-body remnants of binary mergers of spiral-like galaxies. The main set of merger simulations involves a mass-ratio of the progenitors in the range of about 1:1 to 1:5, harboring or not a bulge-like component, and are constructed using a cosmological motivated model. Equal-mass mergers are also considered. Remnants lead to average values for the scaling indices of ~1.6, ~0.6, ~0.7, and ~0.65. These values are consistent with those of K--band observations (Mobasher et al. 1999) of ellipticals: ~1.5, ~0.8, ~0.7, and ~0.60. The b index is, however, not well reproduced. This study does not allow us to establish a conclusive preference for models with or without a bulge as progenitors. Our results indicate that the L--fe and FP scalings might be determined to a large extent by dissipationless processes, a result that appears to be in contradiction to other dissipationless results.