Contribution of Dark Matter Clumps on Heating of Disc Galaxy

The cosmological model predicts that the virialized extent of Milky Way's halo should contain about five hundred dark matter clumps whose mass between 10⁸-10⁹ M_solar, much more greater than number of observed satellites (Moore, 1999; Klyppin, 1999). Existence of a great amount of dark matter clumps within Milky Ways's halo is difficult to be proved observationally. However, their existence can be proved by examining their dynamical effects due to their interaction with disk Galaxy. A realistic galaxy model which satisfy Milky Way's observational constrains and several distributions of dark matter clumps, including the distribution predicted by cosmological model are used to examine the quantitative contribution of their dynamical effect on disk Galaxy. We calculate self-consistent force between particles in disk, particle and clump and between clumps and examine the effect of their interaction for over 10 Gyr. Growing of both velocity dispersion and disk scale height indicates that dark matter clumps play a non-negligible role in the heating of disk Galaxy. We present also long-term growths of disk scale height in solar radius which reach saturation point after some Gyr. References [1] Moore, B et al. 1999, ApJ 524 L19 [2] Klypin, A et al. 1999, ApJ 522, 82