Mass function and bias of dark matter halos for non-Gaussian initial conditions

Details Mass function and bias of dark matter halos for non-Gaussian initial conditions Mass function and bias of dark matter halos for non-Gaussian initial conditions

2009-06-05

arxiv.org/abs/0906.1042v2

Astron.Astrophys.514:A46,2010

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

15 pages

Scientific paper

We revisit the derivation of the mass function and the bias of dark matter halos for non-Gaussian initial conditions. We use a steepest-descent approach to point out that exact results can be obtained for the high-mass tail of the halo mass function and the two-point correlation of massive halos. Focusing on primordial non-Gaussianity of the local type, we check that these results agree with numerical simulations. The high-mass cutoff of the halo mass function takes the same form as the one obtained from the Press-Schechter formalism, but with a linear threshold $\delta_L$ that depends on the definition of the halo. We show that a simple formula, which obeys this high-mass asymptotic and uses the fit obtained for Gaussian initial conditions, matches numerical simulations while keeping the mass function normalized to unity. Next, by deriving the real-space halo two-point correlation in the spirit of Kaiser (1984) and taking a Fourier transform, we obtain good agreement with simulations for the correction to the halo bias due to primordial non-Gaussianity. Therefore, neither the halo mass function nor the bias require an ad-hoc parameter $q$ provided one uses the correct linear threshold $\delta_L$ and pays attention to halo displacements. The nonlinear real-space expression can be useful for checking that the "linearized" bias is a valid approximation. Moreover, it clearly shows how the baryon acoustic oscillation at $\sim 100 h^{-1}$Mpc is amplified by the bias of massive halos and modified by primordial non-Gaussianity. On smaller scales, the correction to the real-space bias roughly scales as $\fNL \, b_M(\fNL=0) \, x^2$. The low-$k$ behavior of the halo bias does not imply a divergent real-space correlation, so that one does not need to introduce counterterms that depend on the survey size.

Affiliated with

Also associated with

No associations

Rating

Mass function and bias of dark matter halos for non-Gaussian initial conditions 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 function and bias of dark matter halos for non-Gaussian initial conditions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mass function and bias of dark matter halos for non-Gaussian initial conditions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-521870