From the Tully-Fisher relation to the Fundamental Plane through Mergers

Abstract

We set up a series of self-consistent N-body simulations to investigate the fundamental plane of merger remnants of spiral galaxies. These last ones are obtained from a theoretical Tully-Fisher relation at z=1, assuming a constant mass-to-light ratio within the LambdaCDM cosmogony. Using a Sersic growth curve and an orthogonal fitting method, we found that the fundamental plane of our merger remnants is described by the relation Re ~ sigma^{1.48} Ie^{-0.75} which is in good agreement with that reported from the Sloan Digital Sky Survey Re ~ sigma^{1.49} Ie^{-0.75}. However, the R^{1/4}-profile leads to a fundamental plane given by Re ~ sigma^{1.79} Ie^{-0.60}. In general, the correlation found in our merger remnants arises from homology breaking (V^2 ~ sigma^nu, Rg ~ Re^eta) in combination with a mass scaling relation between the total and luminous mass, $M ~ ML^gamma. Considering an orthogonal fitting method, it is found that 1.74<nu<1.79, 0.21<eta<0.52 and 0.80<gamma<0.90 depending on the adopted profile (Sersic or R^{1/4}).