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L.D. Shaw (University of Cambridge), J. Weller (University College, London), J.P. Ostriker, P. Bode (Princeton University)
We have identified over 2000 well resolved cluster halos, and also their associated bound subhalos, from the output of a 10243 particle cosmological N-body simulation (of box size 320h-1Mpc and softening length 3.2h-1kpc). We present an algorithm to identify those halos still in the process of relaxing into dynamical equilibrium, and a detailed analysis of the integral and internal physical properties for all the halos in our sample. The majority are prolate, and tend to rotate around their minor principle axis. We find there to be no correlation between the spin and virial mass of the cluster halos and that the higher mass halos are less dynamically relaxed and have a lower concentration. Additionally, the orbital angular momentum of the substructure is typically well aligned with the rotational angular momentum of the 'host' halo. There is also evidence of the transfer of angular momentum from subhalos to their host. Overall, we find that measured halo properties are often significantly influenced by the fraction of mass contained within substructure. Dimensionless properties do depend weakly on the ratio of halo mass (Mh) to our characteristic mass scale (M* = 8x1014h-1Msun). This lack of self-similarity is in the expected sense in that, for example, 'old halos' with Mh / M* << 1 have less substructure than 'young halos' with Mh / M* >> 1.
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The author(s) of this abstract have provided an email address for comments about the abstract: lds@ast.cam.ac.uk
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.