Annu. Rev. Astron. Astrophys. 1994. 32: 531-590
Copyright © 1994 by . All rights reserved

Next Contents Previous


A variety of constraints can be placed on the mass of any dark compact objects in the disk and halo of our own Galaxy by considering their dynamical effects. The constraints are usually calculated on the assumption that the objects are black holes but, as emphasized in Section 6.4, most of them also apply for dark clusters of smaller objects. There are also constraints for dark objects in clusters of galaxies or in the intergalactic medium, though these are weaker. The limits are summarized as upper limits on the density parameter OmegaB(M) for black holes of mass M in Figure 3, where the disk, halo, and cluster dark matter are assumed to have densities of 0.001, 0.1, and 0.2, respectively. Figure 3 updates and - in some respects corrects - Figure 1 of Carr (1978).

Figure 3

Figure 3. A summary of the dynamical constraints on the density parameter OmegaB for black holes of mass M located in the Galactic disk, the Galactic halo, clusters of galaxies, and the intergalactic medium. The total dark matter density in these cases is taken to be 0.001, 0.1, 0.2, and 1, respectively. The limits come from: (a) disk heating; (b) globular cluster disruption; (c) dynamical friction; (d) binary disruption; (e) galaxy distortions; (f) galaxy peculiar velocities; (g) one black hole per disk/halo/cluster/Universe; and (h) comet observations. Limits (b) and (c) are shown by broken lines because they are not so secure. The evaporation limit (i) is nondynamical.

Next Contents Previous