Cold dark matter variant cosmological models  I. Simulations and preliminary comparisons
Abstract
We present two matched sets of five dissipationless simulations each, including four presently favoured minimal modifications to the standard cold dark matter (CDM) scenario. One simulation suite, with a linear box size of 75h^1Mpc, is designed for high resolution and good statistics on the group/poor cluster scale, and the other, with a box size of 300h^1Mpc, is designed for good rich cluster statistics. All runs had 57 million cold particles, and models with massive neutrinos (CHDM2nu) had an additional 113 million hot particles. We consider separately models with massive neutrinos, tilt, curvature, and a nonzero cosmological constant (Lambda=3H^2_0Omega_Lambda) in addition to the standard CDM model. We find that the dark matter in each of our tilted Omega_0+Omega_Lambda=1 (TLambdaCDM) model with Omega_0=0.4, our tilted Omega_01 model (TCDM), and our open Lambda=0 (OCDM) model with Omega=0.5 has too much smallscale power by a factor of ~2, while CHDM2nu and SCDM are acceptable fits. In addition, we take advantage of the large dynamic range in detectable halo masses afforded by the combination of the two sets of simulations to test the PressSchechter approximation. We find good fits at cluster masses for delta_c,g=1.271.35 for a Gaussian filter and delta_c,t=1.571.73 for a top hat filter. However, when we adjust delta_c to obtain a good fit at cluster mass scales, we find that the PressSchechter model overpredicts the number density of haloes compared to the simulations by a weakly cosmologydependent factor of 1.52 at galaxy and group masses. It is impossible to obtain a good fit over the entire range of masses simulated by adjusting delta_c within reasonable bounds.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 November 1998
 DOI:
 10.1046/j.13658711.1998.01998.x
 arXiv:
 arXiv:astroph/9712142
 Bibcode:
 1998MNRAS.301...81G
 Keywords:

 COSMIC MICROWAVE BACKGROUND;
 COSMOLOGY: THEORY;
 DARK MATTER;
 LARGESCALE STRUCTURE OF UNIVERSE;
 Astrophysics
 EPrint:
 18 pages Latex using Monthly Notices style, with 13 inlined EPS figures. This version matches the one accepted by MNRAS. The appendix has been removed and may now be found instead at http://fozzie.gsfc.nasa.gov/thesis/appendixC.ps.gz