Charting the Lyman-alpha escape fraction in the range 2.9<z<6.7 and consequences for the LAE reionisation contribution

Fuente: arXiv
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Autori principali: Goovaerts, Ilias, Thai, Tran Thi, Pello, Roser, Tuan-Anh, Pham, Laporte, Nicolas, Matthee, Jorryt, Nanayakkara, Themiya, Pharo, John
Natura: Preprint
Pubblicazione: 2024
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author Goovaerts, Ilias
Thai, Tran Thi
Pello, Roser
Tuan-Anh, Pham
Laporte, Nicolas
Matthee, Jorryt
Nanayakkara, Themiya
Pharo, John
author_facet Goovaerts, Ilias
Thai, Tran Thi
Pello, Roser
Tuan-Anh, Pham
Laporte, Nicolas
Matthee, Jorryt
Nanayakkara, Themiya
Pharo, John
contents The escape of Lyman-alpha photons at redshifts greater than two is an ongoing subject of study and an important quantity to further understanding of Lyman-alpha emitters (LAEs), the transmission of Lyman-alpha photons through the interstellar medium and intergalactic medium, and the impact these LAEs have on cosmic reionisation. This study aims to assess the Lyman-alpha escape fraction over the redshift range 2.9<z<6.7, focusing on VLT/MUSE-selected, gravitationally lensed, intrinsically faint LAEs. These galaxies are of particular interest as the potential drivers of cosmic reionisation. We assessed the Lyman-alpha escape fraction in two ways: through an individual study of 96 LAEs behind the A2744 lensing cluster, with JWST/NIRCam and HST data, and through a study of the global evolution of the escape fraction using the state-of-the-art luminosity functions for LAEs and the UV-selected `parent' population (dust-corrected). We compared these studies to those in the literature based on brighter samples. We find a negligible redshift evolution of the escape fraction for our individual galaxies; it is likely that it was washed out by significant intrinsic scatter. We observed a more significant evolution towards higher escape fractions with decreasing UV magnitude and fit this relation. When comparing the two luminosity functions to derive the escape fraction in a global sense, we saw agreement with previous literature when integrating the luminosity functions to a bright limit. However, when integrating using a faint limit equivalent to the observational limits of our samples, we observed enhanced escape fraction values, particularly around z~6, where the escape fraction becomes consistent with 100%. This indicates for the faint regimes we sampled that galaxies towards reionisation tend to allow very large fractions of Lyman-alpha photons to escape. (shortened)
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id arxiv_https___arxiv_org_abs_2408_00517
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Charting the Lyman-alpha escape fraction in the range 2.9<z<6.7 and consequences for the LAE reionisation contribution
Goovaerts, Ilias
Thai, Tran Thi
Pello, Roser
Tuan-Anh, Pham
Laporte, Nicolas
Matthee, Jorryt
Nanayakkara, Themiya
Pharo, John
Astrophysics of Galaxies
The escape of Lyman-alpha photons at redshifts greater than two is an ongoing subject of study and an important quantity to further understanding of Lyman-alpha emitters (LAEs), the transmission of Lyman-alpha photons through the interstellar medium and intergalactic medium, and the impact these LAEs have on cosmic reionisation. This study aims to assess the Lyman-alpha escape fraction over the redshift range 2.9<z<6.7, focusing on VLT/MUSE-selected, gravitationally lensed, intrinsically faint LAEs. These galaxies are of particular interest as the potential drivers of cosmic reionisation. We assessed the Lyman-alpha escape fraction in two ways: through an individual study of 96 LAEs behind the A2744 lensing cluster, with JWST/NIRCam and HST data, and through a study of the global evolution of the escape fraction using the state-of-the-art luminosity functions for LAEs and the UV-selected `parent' population (dust-corrected). We compared these studies to those in the literature based on brighter samples. We find a negligible redshift evolution of the escape fraction for our individual galaxies; it is likely that it was washed out by significant intrinsic scatter. We observed a more significant evolution towards higher escape fractions with decreasing UV magnitude and fit this relation. When comparing the two luminosity functions to derive the escape fraction in a global sense, we saw agreement with previous literature when integrating the luminosity functions to a bright limit. However, when integrating using a faint limit equivalent to the observational limits of our samples, we observed enhanced escape fraction values, particularly around z~6, where the escape fraction becomes consistent with 100%. This indicates for the faint regimes we sampled that galaxies towards reionisation tend to allow very large fractions of Lyman-alpha photons to escape. (shortened)
title Charting the Lyman-alpha escape fraction in the range 2.9<z<6.7 and consequences for the LAE reionisation contribution
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2408.00517