Cluster mass function in mixed models

Abstract

We study the cluster mass function in mixed dark matter (MDM) models, using two COBE normalized simulations with Omega_h = 0.26 and n=1.2, and Omega_h = 0.14 and n = 1.05, both with 2 massive nu's (MDM1 and MDM2, respectively). For the sake of comparison, we also simulate a CDM model with spectral index n=0.8 (TCDM), also COBE normalized. We argue that, in our non--hydro simulations, where CDM particles describe both actual CDM and baryons, the galaxy distribution traces CDM particles. Therefore, we use them to define clusters and their velocities to work out cluster masses. As CDM particles are more clustered than HDM and therefore have, in average, greater velocities, this leads to significant differences from PS predictions. Such predictions agree with simulations if both HDM and CDM are used to define clusters. Clusters defined through CDM in MDM models, instead, are less numerous than PS estimates, by a factor ~0.3, at the low mass end; the factor becomes \~0.6-0.8, depending on the mix, on intermediate mass scales (~4-5, h^-1 10^14 Msun) and almost vanishes on the high mass end. Therefore: (i) MDM models expected to overproduce clusters over intermediate scales are viable; (ii) the greater reduction factor at small scales agrees with the observational data dependence on the cluster mass M (which, however, may be partially due to sample incompleteness); (iii) the higher spectral normalization is felt at large scales, where MDM models produce more objects (hence, large clusters) than CDM. MDM1 even exceeds Donahue et al. (1998) findings, while MDM2 is consistent with them. (abridged)

43 pages + 14 figures, accepted for publication in ApJ

References in corpus (5)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Extracting Primordial Density Fluctuations
• The Observational Mass Function of Nearby Galaxy Clusters
• Global cluster morphology and its evolution: X-ray data vs CDM, LCDM and mixed models
• Mixed Models with n>1 and Large Scale Structure constraints

Cited by in corpus (9)

• Cores in warm dark matter haloes: a Catch 22 problem
• The Mira-Titan Universe: Precision Predictions for Dark Energy Surveys
• The Mira-Titan Universe II: Matter Power Spectrum Emulation
• Large-Scale Structure Formation with Massive Neutrinos and Dynamical Dark Energy
• Mass of clusters in simulations
• Abundance and evolution of galaxy clusters in cosmological models with massive neutrino
• Improving initialization and evolution accuracy of cosmological neutrino simulations
• Constraining Lambda using cluster quadrupoles
• Cluster Correlation in Mixed Models