TY - JOUR
T1 - On the evolution of the size of Lyman alpha haloes across cosmic time
T2 - no change in the circumgalactic gas distribution when probed by line emission
AU - Runnholm, Axel
AU - Hayes, Matthew J.
AU - Lin, Yu Heng
AU - Melinder, Jens
AU - Scarlata, Claudia
AU - Adamo, Angela
AU - Augustin, Ramona
AU - Bik, Arjan
AU - Blaizot, Jérémy
AU - Cannon, John M.
AU - Cantalupo, Sebastiano
AU - Garel, Thibault
AU - Gronke, Max
AU - Herenz, Edmund C.
AU - Leclercq, Floriane
AU - Östlin, Göran
AU - Peroux, Celine
AU - Rasekh, Armin
AU - Rutkowski, Michael J.
AU - Verhamme, Anne
AU - Wisotzki, Lutz
N1 - Publisher Copyright:
© The Author(s) 2023. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
PY - 2023/7/1
Y1 - 2023/7/1
N2 - Lyman α (Lyα) is now routinely used as a tool for studying high-redshift galaxies, and its resonant nature means it can trace neutral hydrogen around star-forming galaxies. Integral field spectrograph measurements of high-redshift Lyα emitters indicate that significant extended Lyα halo emission is ubiquitous around such objects. We present a sample of redshift 0.23 to 0.31 galaxies observed with the Hubble Space Telescope selected to match the star formation properties of high-z samples while optimizing the observations for detection of low surface brightness Lyα emission. The Lyα escape fractions range between 0.7 and 37 per cent, and we detect extended Lyα emission around six out of seven targets. We find Lyα halo to UV scale length ratios around 6:1, which is marginally lower than high-redshift observations, and halo flux fractions between 60 and 85 per cent - consistent with high-redshift observations - when using comparable methods. However, our targets show additional extended stellar UV emission: we parametrize this with a new double exponential model. We find that this parametrization does not strongly affect the observed Lyα halo fractions. We find that deeper Hα data would be required to firmly determine the origin of Lyα halo emission; however, there are indications that Hα is more extended than the central FUV profile, potentially indicating conditions favourable for the escape of ionizing radiation. We discuss our results in the context of high-redshift galaxies, cosmological simulations, evolutionary studies of the circumgalactic medium in emission, and the emission of ionizing radiation.
AB - Lyman α (Lyα) is now routinely used as a tool for studying high-redshift galaxies, and its resonant nature means it can trace neutral hydrogen around star-forming galaxies. Integral field spectrograph measurements of high-redshift Lyα emitters indicate that significant extended Lyα halo emission is ubiquitous around such objects. We present a sample of redshift 0.23 to 0.31 galaxies observed with the Hubble Space Telescope selected to match the star formation properties of high-z samples while optimizing the observations for detection of low surface brightness Lyα emission. The Lyα escape fractions range between 0.7 and 37 per cent, and we detect extended Lyα emission around six out of seven targets. We find Lyα halo to UV scale length ratios around 6:1, which is marginally lower than high-redshift observations, and halo flux fractions between 60 and 85 per cent - consistent with high-redshift observations - when using comparable methods. However, our targets show additional extended stellar UV emission: we parametrize this with a new double exponential model. We find that this parametrization does not strongly affect the observed Lyα halo fractions. We find that deeper Hα data would be required to firmly determine the origin of Lyα halo emission; however, there are indications that Hα is more extended than the central FUV profile, potentially indicating conditions favourable for the escape of ionizing radiation. We discuss our results in the context of high-redshift galaxies, cosmological simulations, evolutionary studies of the circumgalactic medium in emission, and the emission of ionizing radiation.
KW - galaxies: haloes - galaxies: starburst
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U2 - 10.1093/mnras/stad1264
DO - 10.1093/mnras/stad1264
M3 - Article
AN - SCOPUS:85159850080
SN - 0035-8711
VL - 522
SP - 4275
EP - 4293
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -