Jeans smoothing of the Ly$\alpha$ forest absorption lines

TL;DR

This paper examines how Jeans smoothing influences the width of Lyα forest lines and assesses its impact on determining intergalactic matter properties, providing refined estimates of key parameters across different redshifts.

Contribution

It introduces a method to account for Jeans smoothing in Lyα forest line analysis, improving the accuracy of intergalactic medium parameter estimation.

Findings

Estimated power-law index γ of the equation of state.

Derived temperature T₀ at mean density.

Set upper limits on the Jeans scale parameter f_J.

Abstract

We investigate a contribution of the Jeans smoothing to the minimal width of Ly$\alpha$ forest lines and discuss how the accounting for this additional broadening affects the inferred parameters of the intergalactic matter equation of state. We estimate a power-law index $\gamma$ of the equation of state, a temperature at the mean density $T_0$ and a hydrogen photoionization rate $\Gamma$ within 4 redshift bins. Furthermore, in each bin we obtain an upper limit on the scale-parameter $f_{\rm J}$, which sets the relation between the Jeans length and the characteristic physical size of the absorber clouds.