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Autori principali: Scarlata, C., Hu, W., Hayes, M. J., Taamoli, S., Khostovan, A. A., Casey, C. M., Faisst, A. L., Kartaltepe, J. S., Lin, Y., Salvato, M., Rafelski, M.
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2501.19303
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author Scarlata, C.
Hu, W.
Hayes, M. J.
Taamoli, S.
Khostovan, A. A.
Casey, C. M.
Faisst, A. L.
Kartaltepe, J. S.
Lin, Y.
Salvato, M.
Rafelski, M.
author_facet Scarlata, C.
Hu, W.
Hayes, M. J.
Taamoli, S.
Khostovan, A. A.
Casey, C. M.
Faisst, A. L.
Kartaltepe, J. S.
Lin, Y.
Salvato, M.
Rafelski, M.
contents We investigate the relationship between the Lyman-alpha (Lya) forest transmission in the intergalactic medium (IGM) and the environmental density of galaxies, focusing on its implications for the measurement of ionizing radiation escape fractions. Using a sample of 268 spectroscopically confirmed background galaxies at 2.7<z<3.0 and a galaxy density map at z~2.5 within the COSMOS field, we measure the Lya transmission photometrically, leveraging the multiwavelength data available from the COSMOS2020 catalog. Our results reveal a weak but statistically significant positive correlation between Lya optical depth and galaxy density contrast, suggesting that overdense regions are enriched in neutral gas, which could bias escape fraction measurements. This emphasizes the need to account for the large-scale structure of the IGM in analyses of ionizing radiation escape fractions, and highlights the advantages of a photometric approach for increasing the number of sampled lines of sight across large fields. The photometric redshifts provided by upcoming all-sky surveys, such as Euclid, will make it possible to account for this effect across widely separated fields.
format Preprint
id arxiv_https___arxiv_org_abs_2501_19303
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Systematic Bias in Ionizing Radiation Escape Fraction Measurements from Foreground Large-Scale Structures
Scarlata, C.
Hu, W.
Hayes, M. J.
Taamoli, S.
Khostovan, A. A.
Casey, C. M.
Faisst, A. L.
Kartaltepe, J. S.
Lin, Y.
Salvato, M.
Rafelski, M.
Astrophysics of Galaxies
We investigate the relationship between the Lyman-alpha (Lya) forest transmission in the intergalactic medium (IGM) and the environmental density of galaxies, focusing on its implications for the measurement of ionizing radiation escape fractions. Using a sample of 268 spectroscopically confirmed background galaxies at 2.7<z<3.0 and a galaxy density map at z~2.5 within the COSMOS field, we measure the Lya transmission photometrically, leveraging the multiwavelength data available from the COSMOS2020 catalog. Our results reveal a weak but statistically significant positive correlation between Lya optical depth and galaxy density contrast, suggesting that overdense regions are enriched in neutral gas, which could bias escape fraction measurements. This emphasizes the need to account for the large-scale structure of the IGM in analyses of ionizing radiation escape fractions, and highlights the advantages of a photometric approach for increasing the number of sampled lines of sight across large fields. The photometric redshifts provided by upcoming all-sky surveys, such as Euclid, will make it possible to account for this effect across widely separated fields.
title Systematic Bias in Ionizing Radiation Escape Fraction Measurements from Foreground Large-Scale Structures
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2501.19303