The effect of helium reionization on the Lyman-alpha forest hydrogen flux statistics

Fuente: arXiv
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Main Authors: Meiksin, Avery, Puchwein, Ewald
Format: Preprint
Published: 2024
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author Meiksin, Avery
Puchwein, Ewald
author_facet Meiksin, Avery
Puchwein, Ewald
contents We assess the impact of QSOs on the high redshift (z > 4) Intergalactic Medium using Monte Carlo realisations of QSO populations and the HeIII regions they generate, applied to the Sherwood-Relics simulations, allowing for uncertainties in the QSO luminosity function, its evolution, and QSO spectra and ages. While QSO luminosity functions based on optical-infrared selection are unable to reproduce the broadening HI Lyman-alpha optical depth distributions at z > 5, much broader distributions are found for the higher numbers of QSOs based on x-ray selection, suggesting a large QSO contribution to the ultra-violet background at z > 5 may offer an alternative to late reionization models to account for the broad HI Lyman-alpha optical depth distributions. Realisations using QSOs based on the higher QSO counts also much better recover the measured pixel flux auto-correlation function at z > 5. The HeIII regions from QSO sources according to both types of luminosity function suppress the pixel flux power spectrum on small scales, k > 0.02 s/km, while enhancing it on larger, both by amounts of up to tens of percent at z > 4, with the magnitude increasing with the intergalactic HeIII filling factor and the boost in temperature within the HeIII regions.
format Preprint
id arxiv_https___arxiv_org_abs_2410_21023
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The effect of helium reionization on the Lyman-alpha forest hydrogen flux statistics
Meiksin, Avery
Puchwein, Ewald
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
We assess the impact of QSOs on the high redshift (z > 4) Intergalactic Medium using Monte Carlo realisations of QSO populations and the HeIII regions they generate, applied to the Sherwood-Relics simulations, allowing for uncertainties in the QSO luminosity function, its evolution, and QSO spectra and ages. While QSO luminosity functions based on optical-infrared selection are unable to reproduce the broadening HI Lyman-alpha optical depth distributions at z > 5, much broader distributions are found for the higher numbers of QSOs based on x-ray selection, suggesting a large QSO contribution to the ultra-violet background at z > 5 may offer an alternative to late reionization models to account for the broad HI Lyman-alpha optical depth distributions. Realisations using QSOs based on the higher QSO counts also much better recover the measured pixel flux auto-correlation function at z > 5. The HeIII regions from QSO sources according to both types of luminosity function suppress the pixel flux power spectrum on small scales, k > 0.02 s/km, while enhancing it on larger, both by amounts of up to tens of percent at z > 4, with the magnitude increasing with the intergalactic HeIII filling factor and the boost in temperature within the HeIII regions.
title The effect of helium reionization on the Lyman-alpha forest hydrogen flux statistics
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2410.21023