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Main Authors: Nakashima, Koichiro, Nishizawa, Atsushi J., Nagamine, Kentaro, Oku, Yuri, Shimizu, Ikkoh
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2410.16740
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author Nakashima, Koichiro
Nishizawa, Atsushi J.
Nagamine, Kentaro
Oku, Yuri
Shimizu, Ikkoh
author_facet Nakashima, Koichiro
Nishizawa, Atsushi J.
Nagamine, Kentaro
Oku, Yuri
Shimizu, Ikkoh
contents The Ly$α$ forest, a series of HI absorption lines in the quasar spectra, is a powerful tool for probing the large-scale structure of the intergalactic medium. Its three-dimensional (3D) correlation and cross-correlations with quasars allow precise measurements of the baryon acoustic oscillation feature and redshift space distortions at redshifts $z>2$. Understanding small-scale astrophysical phenomena, such as star formation and feedback, is crucial for full-shape analyses. In this study, we measure the 3D auto-power spectrum of the Ly$α$ forest and its cross-power spectrum with halos using hydrodynamic simulations from the GADGET3-OSAKA code, which includes models for star formation and supernova feedback. Across five astrophysical models, we find significant deviations from the Fiducial model, with $5-10\,\%$ differences for wavenumbers $k>2\,h\mathrm{Mpc}^{-1}$ in the Ly$α$ auto-power spectrum. The Ly$α\,\times\,$halo cross-power spectra show even larger deviations, exceeding $10\,\%$ in some cases. Using the fitting models of Arinyo-i-Prats et al. (2015) and Givans et al. (2022), we jointly fit the Ly$α$ auto- and Ly$α$ $\times$ halo cross-power spectra, and assess the accuracy of the estimated $fσ_8$ parameter by comparing it with the ground truth from the simulations, while varying the maximum wavenumber $k_\mathrm{max}$ and minimum halo mass $M_h$. Our results demonstrate that the extended model of Givans et al. (2022) is highly effective in reproducing $fσ_8$ at $k_\mathrm{max}\leq3.0\,h\mathrm{Mpc}^{-1}$ for $M_h>10^{10.5} M_\odot$, and remains robust against astrophysical uncertainties.
format Preprint
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publishDate 2024
record_format arxiv
spellingShingle Lyman-$α$ forest power spectrum and its cross-correlation with dark matter halos in different astrophysical models
Nakashima, Koichiro
Nishizawa, Atsushi J.
Nagamine, Kentaro
Oku, Yuri
Shimizu, Ikkoh
Cosmology and Nongalactic Astrophysics
The Ly$α$ forest, a series of HI absorption lines in the quasar spectra, is a powerful tool for probing the large-scale structure of the intergalactic medium. Its three-dimensional (3D) correlation and cross-correlations with quasars allow precise measurements of the baryon acoustic oscillation feature and redshift space distortions at redshifts $z>2$. Understanding small-scale astrophysical phenomena, such as star formation and feedback, is crucial for full-shape analyses. In this study, we measure the 3D auto-power spectrum of the Ly$α$ forest and its cross-power spectrum with halos using hydrodynamic simulations from the GADGET3-OSAKA code, which includes models for star formation and supernova feedback. Across five astrophysical models, we find significant deviations from the Fiducial model, with $5-10\,\%$ differences for wavenumbers $k>2\,h\mathrm{Mpc}^{-1}$ in the Ly$α$ auto-power spectrum. The Ly$α\,\times\,$halo cross-power spectra show even larger deviations, exceeding $10\,\%$ in some cases. Using the fitting models of Arinyo-i-Prats et al. (2015) and Givans et al. (2022), we jointly fit the Ly$α$ auto- and Ly$α$ $\times$ halo cross-power spectra, and assess the accuracy of the estimated $fσ_8$ parameter by comparing it with the ground truth from the simulations, while varying the maximum wavenumber $k_\mathrm{max}$ and minimum halo mass $M_h$. Our results demonstrate that the extended model of Givans et al. (2022) is highly effective in reproducing $fσ_8$ at $k_\mathrm{max}\leq3.0\,h\mathrm{Mpc}^{-1}$ for $M_h>10^{10.5} M_\odot$, and remains robust against astrophysical uncertainties.
title Lyman-$α$ forest power spectrum and its cross-correlation with dark matter halos in different astrophysical models
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2410.16740