SCALING RELATIONS IN DISSIPATIONLESS SPIRAL-LIKE GALAXY MERGERS

We determine both representations of the Fundamental Plane [FP; R-e proportional to sigma(a)(0) < I >(-b)(e) and R-e proportional to (sigma(2)(0) < I >(-1)(e))(lambda)] and the luminosity-effective phase-space density (L proportional to f(e)(-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 < a > approximate to 1.6, < b > approximate to 0.6, approximate to 0.7, and approximate to 0.65. These values are consistent with those of K-band observations of ellipticals: < a > approximate to 1.5, < b > approximate to 0.8, approximate to 0.7, and approximate to 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-f(e) 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.