{"publication_identifier":{"eissn":["1365-2966"],"issn":["0035-8711"]},"extern":"1","type":"journal_article","date_updated":"2022-08-19T07:53:04Z","volume":465,"abstract":[{"lang":"eng","text":"We study the production rate of ionizing photons of a sample of 588 Hα emitters (HAEs) and 160 Lyman-α emitters (LAEs) at z = 2.2 in the COSMOS field in order to assess the implied emissivity from galaxies, based on their ultraviolet (UV) luminosity. By exploring the rest-frame Lyman Continuum (LyC) with GALEX/NUV data, we find fesc < 2.8 (6.4) per cent through median (mean) stacking. By combining the Hα luminosity density with intergalactic medium emissivity measurements from absorption studies, we find a globally averaged 〈fesc〉 of 5.9+14.5−4.2 per cent at z = 2.2 if we assume HAEs are the only source of ionizing photons. We find similarly low values of the global 〈fesc〉 at z ≈ 3–5, also ruling out a high 〈fesc〉 at z < 5. These low escape fractions allow us to measure ξion, the number of produced ionizing photons per unit UV luminosity, and investigate how this depends on galaxy properties. We find a typical ξion ≈ 1024.77 ± 0.04 Hz erg−1 for HAEs and ξion ≈ 1025.14 ± 0.09 Hz erg−1 for LAEs. LAEs and low-mass HAEs at z = 2.2 show similar values of ξion as typically assumed in the reionization era, while the typical HAE is three times less ionizing. Due to an increasing ξion with increasing EW(Hα), ξion likely increases with redshift. This evolution alone is fully in line with the observed evolution of ξion between z ≈ 2 and 5, indicating a typical value of ξion ≈ 1025.4 Hz erg−1 in the reionization era."}],"publication":"Monthly Notices of the Royal Astronomical Society","publication_status":"published","_id":"11564","doi":"10.1093/mnras/stw2973","author":[{"full_name":"Matthee, Jorryt J","first_name":"Jorryt J","orcid":"0000-0003-2871-127X","last_name":"Matthee","id":"7439a258-f3c0-11ec-9501-9df22fe06720"},{"last_name":"Sobral","first_name":"David","full_name":"Sobral, David"},{"full_name":"Best, Philip","first_name":"Philip","last_name":"Best"},{"last_name":"Khostovan","first_name":"Ali Ahmad","full_name":"Khostovan, Ali Ahmad"},{"first_name":"Iván","full_name":"Oteo, Iván","last_name":"Oteo"},{"last_name":"Bouwens","full_name":"Bouwens, Rychard","first_name":"Rychard"},{"last_name":"Röttgering","full_name":"Röttgering, Huub","first_name":"Huub"}],"month":"03","date_created":"2022-07-12T12:12:14Z","citation":{"ieee":"J. J. Matthee <i>et al.</i>, “The production and escape of Lyman-Continuum radiation from star-forming galaxies at z ∼ 2 and their redshift evolution,” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 465, no. 3. Oxford University Press, pp. 3637–3655, 2017.","ama":"Matthee JJ, Sobral D, Best P, et al. The production and escape of Lyman-Continuum radiation from star-forming galaxies at z ∼ 2 and their redshift evolution. <i>Monthly Notices of the Royal Astronomical Society</i>. 2017;465(3):3637-3655. doi:<a href=\"https://doi.org/10.1093/mnras/stw2973\">10.1093/mnras/stw2973</a>","mla":"Matthee, Jorryt J., et al. “The Production and Escape of Lyman-Continuum Radiation from Star-Forming Galaxies at z ∼ 2 and Their Redshift Evolution.” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 465, no. 3, Oxford University Press, 2017, pp. 3637–55, doi:<a href=\"https://doi.org/10.1093/mnras/stw2973\">10.1093/mnras/stw2973</a>.","short":"J.J. Matthee, D. Sobral, P. Best, A.A. Khostovan, I. Oteo, R. Bouwens, H. Röttgering, Monthly Notices of the Royal Astronomical Society 465 (2017) 3637–3655.","apa":"Matthee, J. J., Sobral, D., Best, P., Khostovan, A. A., Oteo, I., Bouwens, R., &#38; Röttgering, H. (2017). The production and escape of Lyman-Continuum radiation from star-forming galaxies at z ∼ 2 and their redshift evolution. <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press. <a href=\"https://doi.org/10.1093/mnras/stw2973\">https://doi.org/10.1093/mnras/stw2973</a>","chicago":"Matthee, Jorryt J, David Sobral, Philip Best, Ali Ahmad Khostovan, Iván Oteo, Rychard Bouwens, and Huub Röttgering. “The Production and Escape of Lyman-Continuum Radiation from Star-Forming Galaxies at z ∼ 2 and Their Redshift Evolution.” <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press, 2017. <a href=\"https://doi.org/10.1093/mnras/stw2973\">https://doi.org/10.1093/mnras/stw2973</a>.","ista":"Matthee JJ, Sobral D, Best P, Khostovan AA, Oteo I, Bouwens R, Röttgering H. 2017. The production and escape of Lyman-Continuum radiation from star-forming galaxies at z ∼ 2 and their redshift evolution. Monthly Notices of the Royal Astronomical Society. 465(3), 3637–3655."},"acknowledgement":"We thank the referee for the many helpful and constructive comments which have significantly improved this paper. JM acknowledges the support of a Huygens PhD fellowship from Leiden University. DS acknowledges financial support from the Netherlands Organization for Scientific research (NWO) through a Veni fellowship and from FCT through an FCT Investigator Starting Grant and Start-up Grant (IF/01154/2012/CP0189/CT0010). PNB is grateful for support from the UK STFC via grant ST/M001229/1. IO acknowledges support from the European Research Council in the form of the Advanced Investigator Programme, 321302, COSMICISM. The authors thank Andreas Faisst, Michael Rutkowski and Andreas Sandberg for answering questions related to this work and Daniel Schaerer and Mark Dijkstra for discussions. We acknowledge the work that has been done by both the COSMOS team in assembling such large, state-of-the-art multi-wavelength data set, as this has been crucial for the results presented in this paper. We have benefited greatly from the public available programming language PYTHON, including the NUMPY, MATPLOTLIB, PYFITS, SCIPY (Jones et al. 2001; Hunter 2007; Van Der Walt, Colbert & Varoquaux 2011) and ASTROPY (Astropy Collaboration et al. 2013) packages, the astronomical imaging tools SEXTRACTOR and SWARP (Bertin & Arnouts 1996;\r\nBertin 2010) and the TOPCAT analysis program (Taylor 2013).","article_processing_charge":"No","oa":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","external_id":{"arxiv":["1605.08782"]},"status":"public","page":"3637-3655","language":[{"iso":"eng"}],"intvolume":"       465","oa_version":"Preprint","issue":"3","scopus_import":"1","quality_controlled":"1","title":"The production and escape of Lyman-Continuum radiation from star-forming galaxies at z ∼ 2 and their redshift evolution","main_file_link":[{"url":"https://arxiv.org/abs/1605.08782","open_access":"1"}],"keyword":["Space and Planetary Science","Astronomy and Astrophysics","galaxies: evolution","galaxies: high-redshift","cosmology: observations","dark ages","reionization","first stars"],"date_published":"2017-03-01T00:00:00Z","day":"01","article_type":"original","publisher":"Oxford University Press","year":"2017"}