Mass Accretion Rates and Histories of Dark Matter Haloes

Details Mass Accretion Rates and Histories of Dark Matter Haloes Mass Accretion Rates and Histories of Dark Matter Haloes

2009-02-23

arxiv.org/abs/0902.3659v2

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

12 pages, 13 figures, Accepted in MNRAS

Scientific paper

We use the extensive catalog of dark matter haloes from the Millennium simulation to investigate the statistics of the mass accretion histories (MAHs) and accretion rates of ~500,000 haloes from redshift z=0 to 6. We find only about 25% of the haloes to have MAHs that are well described by a 1-parameter exponential form. For the rest of the haloes, between 20% (Milky-Way mass) to 50% (cluster mass) experience late-time growth that is steeper than an exponential, whereas the remaining haloes show plateau-ed late-time growth that is shallower than an exponential. The haloes with slower late-time growth tend to reside in denser environments, suggesting that either tidal stripping or the "hotter" dynamics are suppressing the accretion rate of dark matter onto these haloes. These deviations from exponential growth are well fit by introducing a second parameter: M(z) \propto (1+z)^beta exp(-gamma z). The full distribution of beta and gamma as a function of halo mass is provided. From the analytic form of M(z), we obtain a simple formula for the mean accretion rate of dark matter, dM/dt, as a function of redshift and mass. At z=0, this rate is 42 Msun/yr for 1e12 Msun haloes, which corresponds to a mean baryon accretion rate of dMbaryon/dt=7 Msun/yr. This mean rate increases approximately as (1+z)^1.5 at low z and (1+z)^2.5 at high z, reaching dMbaryon/dt = 27, 69, and 140 Msun/yr at z=1, 2, and 3. The specific rate depends on halo mass weakly: dlogM/dt \propto M^0.127. Results for the broad distributions about the mean rates are also discussed.

Affiliated with

Also associated with

No associations

Rating

Mass Accretion Rates and Histories of Dark Matter Haloes 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 Mass Accretion Rates and Histories of Dark Matter Haloes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mass Accretion Rates and Histories of Dark Matter Haloes will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-583773