To this end, they have procured a grant from the Fund for Astrophysical Research for the purchase of additional computer hardware. For isothermal stellar systems, they derive an expression for the instantaneous dynamical friction force, in terms of the correlation function of fluctuating forces, that does not require any of these approximations. J. Magorrian , S. Tremaine , K. Gebhardt, D. Richstone, and S. Faber have analyzed a sample of 26 galaxies with Hubble Telescope photometry and ground-based spectroscopy, to look for dynamical evidence of a massive central dark object. The models imply that massive dark objects are present in 19 of the 26 galaxies, and satisfy an approximate correlation . Of the remaining seven galaxies, two are consistent with and five cannot described by the models, most probably due to anisotropy or triaxiality.
Work is underway to test whether more general models strengthen or weaken the correlation.
The galaxy photocentre lies between the two peaks and the nuclear morphology is independent of colour. These results suggest that the double nucleus represents the ansae or lobes of a nearly edge-on disk. The disk appears to be eccentric, which in turn requires that NGC 4486B contains a massive dark object, so that the potential field is nearly Keplerian. The results confirm an earlier claim by Kormendy that there is a dark object at the centre, at five times higher resolution. The central velocity dispersion measured by HST is km s .