The environment and redshift dependence of accretion onto dark matter halos and subhalos

Details The environment and redshift dependence of accretion onto dark matter halos and subhalos The environment and redshift dependence of accretion onto dark matter halos and subhalos

2011-06-23

arxiv.org/abs/1106.4814v1

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

16 pages, 11 figures. Accepted for publication in MNRAS

Scientific paper

A dark-matter-only Horizon Project simulation is used to investigate the environment- and redshift- dependence of accretion onto both halos and subhalos. These objects grow in the simulation via mergers and via accretion of diffuse non-halo material, and we measure the combined signal from these two modes of accretion. It is found that the halo accretion rate varies less strongly with redshift than predicted by the Extended Press-Schechter (EPS) formalism and is dominated by minor-merger and diffuse accretion events at z=0, for all halos. These latter growth mechanisms may be able to drive the radio-mode feedback hypothesised for recent galaxy-formation models, and have both the correct accretion rate and form of cosmological evolution. The low redshift subhalo accretors in the simulation form a mass-selected subsample safely above the mass resolution limit that reside in the outer regions of their host, with ~70% beyond their host's virial radius, where they are probably not being significantly stripped of mass. These subhalos accrete, on average, at higher rates than halos at low redshift and we argue that this is due to their enhanced clustering at small scales. At cluster scales, the mass accretion rate onto halos and subhalos at low redshift is found to be only weakly dependent on environment and we confirm that at z~2 halos accrete independently of their environment at all scales, as reported by other authors. By comparing our results with an observational study of black hole growth, we support previous suggestions that at z>1, dark matter halos and their associated central black holes grew coevally, but show that by the present day, dark matter halos could be accreting at fractional rates that are up to a factor 3-4 higher than their associated black holes.

Affiliated with

Also associated with

No associations

Rating

The environment and redshift dependence of accretion onto dark matter halos and subhalos 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 The environment and redshift dependence of accretion onto dark matter halos and subhalos, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The environment and redshift dependence of accretion onto dark matter halos and subhalos will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-393269