Self-Similar Bumps and Wiggles: Isolating the Evolution of the BAO Peak with Power-law Initial Conditions

Understand

Motivated by cosmological surveys that demand accurate theoretical modeling of the baryon acoustic oscillation (BAO) feature in galaxy clustering, we analyze N-body simulations in which a BAO-like gaussian bump modulates the linear theory correlation function \xi_L(r)=(r_0/r)^{n+3} of an underlying self-similar model with initial power spectrum P(k)=A k^n.

• These simulations test physical and analytic descriptions of BAO evolution far beyond the range of most studies, since we consider a range of underlying power spectra (n=-0.5, -1, -1.5) and evolve simulations to large effective correlation amplitudes (equivalent to \sigma_8=4-12 for r_bao = 100 Mpc/h).
• In all cases, non-linear evolution flattens and broadens the BAO bump in \xi(r) while approximately preserving its area.
• This evolution resembles a "diffusion" process in which the bump width \sigma_bao is the quadrature sum of the linear theory width and a length proportional to the rms relative displacement \Sigma_pair(r_bao}) of particle pairs separated by r_bao.