The effect of inhomogeneous reionization on the Lyman α forest power spectrum at redshift z > 4: implications for thermal parameter recovery

ABSTRACT We use the Sherwood–Relics suite of hybrid hydrodynamical and radiative transfer simulations to model effect inhomogeneous reionization on 1D power spectrum Lyman α (Lyα) forest transmitted flux at redshifts 4.2 ≤ z 5. Relative models that assume a homogeneous ultraviolet background, suppresses small scales, k ∼ 0.1 km−1 s, by ∼10 per cent because spatial variations in thermal broadening kernel divergent peculiar velocity field associated with overpressurized intergalactic gas. On larger $k\lt 0.03\rm \, km^{-1}\, s$, is instead enhanced 10–50 large-scale neutral hydrogen fraction. The must therefore be accounted for analyses forthcoming high precision measurements. provide correction Lyα 4.1 5.4 can easily applied within other parameter inference frameworks using similar models. perform Bayesian analysis mock data assess extent systematic biases may arise measurements medium if ignoring this correction. At scales probed current high-resolution > 4, $0.006 \le 0.2 \rm we find does not introduce any significant bias recovery measurement uncertainties cent. However, 5 uncertainties, ∼1σ shifts between estimated true parameters occur.