Playground of Lognormal Seminumerical Simulations of~the~Lyman~$\alpha$ Forest: Thermal History of the Intergalactic Medium

TL;DR

This paper demonstrates that lognormal seminumerical simulations can effectively recover the thermal history and Jeans length of the intergalactic medium from quasar absorption spectra, offering a fast tool for cosmological analysis.

Contribution

It introduces a seminumerical simulation approach for Lyman-alpha forest spectra that accurately estimates thermal parameters and Jeans length, suitable for large-scale data interpretation.

Findings

Lognormal simulations recover thermal parameters effectively.

Synthetic spectra match observed flux power spectra.

Approach can infer cosmological parameters from data.

Abstract

This study aims to test a potential application of lognormal seminumerical simulations to recover the thermal parameters and Jeans length. This could be suitable for generating large number of synthetic spectra with various input data and parameters, and thus ideal for interpreting the high-quality data obtained from QSO absorption spectra surveys. We use a seminumerical approach to simulate absorption spectra of quasars at redshifts $ 3 \leq z \leq 5$. These synthetic spectra are compared with the 1D flux power spectra and using the Markov Chain Monte Carlo analysis method we determine the temperature at mean density, slope of the temperature-density relation and Jeans length. Our best-fit model is also compared with the evolution of the temperature of the intergalactic medium from various UVB models. We show that the lognormal simulations can effectively recover thermal parameters and Jeans length. Besides, by comparing the synthetic flux power spectra with observations from Baryon Oscillation Spectroscopy Survey we found, that such an approach can be also used for the cosmological parameter inference.