Thermal state of the intergalactic medium at $z\sim2-4$

Understand

We present a new method to infer parameters of the temperature-density relation in the intergalactic medium in the post-reionization epoch at $z\sim 2-4$.

• This method is based on the analysis of the Ly$\alpha$ absorbers distribution over column densities and Doppler parameters by the model joint probability density function.
• This approach allows us to measure the power-law index $\gamma$ of the temperature-density relation and a certain combination of the temperature at the mean density $T_0$ and hydrogen photoionization rate $\Gamma$.
• To estimate $T_0$ and $\Gamma$ separately, we employ measurements of the Ly$\alpha$ forest effective opacity and the model gas probability density function.