The MBH-σc relation as a constraint on the formation of elliptical galaxies

Most elliptical galaxies contain central black holes, whose masses scale proportionally to the observed central velocity dispersions of the host galaxies according to the so-called M-BH-sigma (c) relation. Here we discuss some consequences that can be derived by combining the M-BH-sigma (c) relation with the scaling relation describing the fundamental plane of elliptical galaxies. In particular, the possibility of substantial dissipationless merging in the formation and evolution of elliptical galaxies is discussed. We enforce the merger end products to satisfy the two scaling relations mentioned above, and a major role of dissipation in galaxy formation is strongly suggested by our analysis. Moreover, we show that existing observational data may shed some light on the complex process of black hole merging.