Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-07-08
Mon.Not.Roy.Astron.Soc.366:1455-1464,2006
Astronomy and Astrophysics
Astrophysics
11 pages, 12 figures; v2: major revision matching version accepted by MNRAS
Scientific paper
10.1111/j.1365-2966.2005.09943.x
We investigate the properties of the pairwise velocity dispersion as a function of galaxy luminosity in the context of a halo model. We derive the distribution of velocities of pairs at a given separation taking into account both one-halo and two-halo contributions. We show that pairwise velocity distribution in real space is a complicated mixture of host-satellite, satellite-satellite and two-halo pairs. The peak value is reached at around 1$h^{-1}$Mpc and does not reflect the velocity dispersion of a typical halo hosting these galaxies, but is instead dominated by the satellite-satellite pairs in high mass clusters. This is true even for cross-correlations between bins separated in luminosity. As a consequence the velocity dispersion at a given separation can decrease with luminosity, even if the underlying typical halo host mass is increasing, in agreement with recent observations. We compare our findings to numerical simulations and find a good agreement. Numerical simulations also suggest a luminosity dependent velocity bias, which depends on the subhalo mass. We develop models of the auto- and cross-correlation function of luminosity subsamples of galaxies in the observable $r_\proj - \pi$ space and calculate the inferred velocity dispersion as a function of wave vector if dispersion model is fit to the redshift space power spectrum. We find that so derived pairwise velocity dispersion also exhibits a bump at $k\sim 1 h/{\rm Mpc}$.
Seljak Uros
Slosar Anze
Tasitsiomi Argyro
No associations
LandOfFree
Pairwise velocities in the Halo Model: Luminosity and Scale Dependence does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Pairwise velocities in the Halo Model: Luminosity and Scale Dependence, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pairwise velocities in the Halo Model: Luminosity and Scale Dependence will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-374520