The Diversity and Similarity of Simulated Cold Dark Matter Halos

Details The Diversity and Similarity of Simulated Cold Dark Matter Halos The Diversity and Similarity of Simulated Cold Dark Matter Halos

2008-10-08

arxiv.org/abs/0810.1522v2

Astronomy and Astrophysics

Astrophysics

Submitted to MNRAS. Minor revisions. Conclusions unchanged. Pictures, movies, and further information on the Aquarius Project

Scientific paper

We study the mass, velocity dispersion, and anisotropy profiles of $\Lambda$CDM halos using a suite of N-body simulations of unprecedented numerical resolution (the {\it Aquarius Project}). Our analysis confirms a number of results claimed by earlier work, and clarifies a few issues where conflicting claims may be found in the recent literature. The spherically-averaged density profile becomes progressively shallower inwards and, at the innermost resolved radius, the logarithmic slope is $\gamma \equiv -$d$\ln\rho/$d$\ln r \simlt 1$. Asymptotic inner slopes as steep as the recently claimed $\rho \propto r^{-1.2}$ are clearly ruled out. The radial dependence of $\gamma$ is well approximated by a power-law, $\gamma \propto r^{\alpha}$ (the Einasto profile). The shape parameter, $\alpha$, varies slightly but significantly from halo to halo, implying that the mass profiles of $\Lambda$CDM halos are not strictly universal: different halos cannot, in general, be rescaled to look identical. Departures from similarity are also seen in velocity dispersion profiles and correlate with those in density profiles so as to preserve a power-law form for the spherically averaged pseudo-phase-space density, $\rho/\sigma^3\propto r^{-1.875}$. Our conclusions are reliable down to radii below 0.4% of the virial radius, providing well-defined predictions for halo structure when baryonic effects are neglected, and thus an instructive theoretical template against which the modifications induced by the baryonic components of real galaxies can be judged.

Affiliated with

Also associated with

No associations

Rating

The Diversity and Similarity of Simulated Cold Dark Matter Halos 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 Diversity and Similarity of Simulated Cold Dark Matter Halos, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Diversity and Similarity of Simulated Cold Dark Matter Halos will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-460096