Scalings between Physical and their Observationally related Quantities of Merger Remnants

Abstract

We present scaling relations between the virial velocity (V) and the one-dimensional central velocity dispersion (Sig0); the gravitational radius (Rv) and the effective radius (Re); and the total mass (M) and the luminous mass (ML) found in N-body simulations of binary mergers of spiral galaxies. These scalings are of the form V^2 ~ Sig0^alpha, Rv ~ Re^beta and M ~ ML^gamma. The particlar values obtained for (alpha,beta,gamma) depend on the method of fitting used [ordinary least-squares (ols) or orthogonal distance regression (odr)], the assumed profile [de Vaucouleurs (deV) or Sersic (S)], and the size of the radial interval where the fit is done. The alpha and gamma indexes turn out more sensitive to the fitting procedure, obtaining for the ols a mean alpha_ols=1.51 and gamma_ols=0.69, while for the odr alpha_odr=2.35 and gamma_odr=0.76. The beta index depends more on the adopted type of profile, with beta_deV=0.13 and beta_S=0.27. We conclude that dissipationless formed remnants of mergers have a strong breaking of structural and kinematical homology.

10 pages, 5 figures. Accepted in RMxAA