Dynamical Constraints on Dark Matter in Compact Objects

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Abstract
Many of the baryons in the universe are dark and at least some of the dark baryons could be in the form of compact objects. Such objects could be in various locations—galactic disks, galactic halos, clusters of galaxies, or intergalactic space—and each of these is associated with a dark matter problem. For each site we consider the various dynamical constraints that can be placed on the fraction of the dark matter in compact objects of different mass. Small compact objects in the Galaxy are constrained byupper limits on their encounter rate with the Earth and solar system since they would resemble meteors or comets. Larger objects are constrained by the disruptive or disturbing effects they would have on various astronomical systems. For disk objects, the most interesting constraints come from the disruption of binary stars or open star clusters. For halo objects, they come from the disruption of globular clusters, the heating of the Galactic disk, and their accumulation in the Galactic nucleus as a result of dynamical friction. For cluster objects, they come from the tidal distortion and disruption of galaxies. For intergalactic objects, they come from the upper limit on the peculiar motions induced in galaxies. We also apply these limits to the situation in which the compact objects are clusters of smaller objects.