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          Institute: MPI für Astrophysik     Collection: Cosmology     Display Documents

ID: 10975.0, MPI für Astrophysik / Cosmology
On the distribution of haloes, galaxies and mass
Authors:Casas-Miranda, R.; Mo, H. J.; Sheth, R. K.; Börner, G.
Date of Publication (YYYY-MM-DD):2002
Title of Journal:Monthly Notices of the Royal Astronomical Society
Journal Abbrev.:Mon. Not. Roy. Astron. Soc.
Issue / Number:4
Start Page:730
End Page:738
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:The stochasticity in the distribution of dark haloes in the cosmic density field is reflected in the distribution function P-V (N (h) \delta (m) ), which gives the probability of finding N (h) haloes in a volume V with mass density contrast delta (m) . We study the properties of this function using high- resolution N -body simulations, and find that P-V (N (h) \delta (m) ) is significantly non-Poisson. The ratio between the variance and the mean goes from similar to1 (Poisson) at 1+delta (m) <<1 to <1 (sub-Poisson) at 1+delta (m) similar to1< to >1 (super-Poisson) at 1+δ (m) >>1. The mean bias relation is found to be well described by halo bias models based on the Press-Schechter formalism. The sub-Poisson variance can be explained as a result of halo exclusion, while the super-Poisson variance at high delta (m) may be explained as a result of halo clustering. A simple phenomenological model is proposed to describe the behaviour of the variance as a function of delta (m) . Galaxy distribution in the cosmic density field predicted by semi-analytic models of galaxy formation shows similar stochastic behaviour. We discuss the implications of the stochasticity in halo bias to the modelling of higher order moments of dark haloes and of galaxies.
Free Keywords:galaxies : clusters : general; galaxies : formation; cosmology : theory; dark matter
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astrophysik
External Affiliations:Max Planck Inst Astrophys, Karl Schwarzschild Str 1, D-85741; Garching, Germany; Max Planck Inst Astrophys, D-85741 Garching, Germany; NASA, Fermilab Astrophys Grp, Batavia, IL 60510 USA
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