Mass-Dependent Baryon Acoustic Oscillation Signal and Halo Bias

TL;DR

This study uses N-body simulations to analyze how baryon acoustic oscillations and halo bias depend on mass, revealing scale-dependent effects that are crucial for interpreting large-scale structure observations.

Contribution

It provides the first detailed characterization of mass-dependent BAO damping and bias modulation in halo two-point statistics using simulations.

Findings

Nonlinear damping of BAO is less severe for halos than dark matter.

Halo bias drops around 90 Mpc/h, with a 4% decrease for M>10^{14} Msun/h.

Bias modulation depends on halo mass and scale, affecting large-scale structure measurements.

Abstract

We characterize the baryon acoustic oscillations (BAO) feature in halo two-point statistics using N-body simulations. We find that nonlinear damping of the BAO signal is less severe for halos in the mass range we investigate than for dark matter. The amount of damping depends weakly on the halo mass. The correlation functions show a mass-dependent drop of the halo clustering bias below roughly 90 Mpc/h, which coincides with the scale of the BAO trough. The drop of bias is 4% for halos with mass M>10^{14} Msun/h and reduces to roughly 2% for halos with mass M>10^{13} Msun/h. In contrast, halo biases in simulations without BAO change more smoothly around 90 Mpc/h. In Fourier space, the bias of M>10^{14} Msun/h halos decreases smoothly by 11% from wavenumber k = 0.012 h/Mpc to 0.2 h/Mpc, whereas that of M>10^{13} Msun/h halos decreases by less than 4% over the same range. By comparing the halo biases in pairs of otherwise identical simulations, one with and the other without BAO, we also observe a modulation of the halo bias. These results suggest that precise calibrations of the mass-dependent BAO signal and scale-dependent bias on large scales would be needed for interpreting precise measurements of the two-point statistics of clusters or massive galaxies in the future.