The Low-redshift Lyman Continuum Survey. I. New, Diverse Local Lyman Continuum Emitters

Sophia R. Flury , Anne E. Jaskot , Harry C. Ferguson , Gábor Worseck , Kirill Makan , John Chisholm , Alberto Saldana-Lopez , Daniel Schaerer , Stephan Mccandliss , Bingjie Wang , N. M. Ford , Timothy Heckman , Zhiyuan Ji , Mauro Giavalisco , Ricardo Amorin , Hakim Atek (1) , Jeremy Blaizot (2) , Sanchayeeta Borthakur , Cody Carr , Marco Castellano , Stefano Cristiani , Stephane de Barros , Mark Dickinson , Steven L. Finkelstein , Brian Fleming , Fabio Fontanot , Thibault Garel , Andrea Grazian , Matthew Hayes , Alaina Henry , Valentin Mauerhofer , Genoveva Micheva , M. S. Oey , Goran Ostlin , Casey Papovich , Laura Pentericci , Swara Ravindranath , Joakim Rosdahl (2) , Michael Rutkowski , Paola Santini , Claudia Scarlata , Harry Teplitz , Trinh Thuan , Maxime Trebitsch , Eros Vanzella , Anne Verhamme (2) , Xinfeng Xu

1 IAP - Institut d'Astrophysique de Paris
2 CRAL - Centre de Recherche Astrophysique de Lyon

The origins of Lyman continuum (LyC) photons responsible for the reionization of the universe are as of yet unknown and highly contested. Detecting LyC photons from the Epoch of Reionization is not possible due to absorption by the intergalactic medium, which has prompted the development of several indirect diagnostics to infer the rate at which galaxies contribute LyC photons to reionize the universe by studying lower-redshift analogs. We present the Low-redshift Lyman Continuum Survey (LzLCS) comprising measurements made with the Hubble Space Telescope Cosmic Origins Spectrograph for a z = 0.2-0.4 sample of 66 galaxies. After careful processing of the far-UV spectra, we obtain a total of 35 Lyman continuum emitters (LCEs) detected with 97.725% confidence, nearly tripling the number of known local LCEs. We estimate escape fractions from the detected LyC flux and upper limits on the undetected LyC flux, finding a range of LyC escape fractions up to 50%. Of the 35 LzLCS LCEs, 12 have LyC escape fractions greater than 5%, more than doubling the number of known local LCEs with cosmologically relevant LyC escape.

Keywords: Reionization; Galactic and extragalactic astronomy; Ultraviolet astronomy; Hubble Space Telescope

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

Sophia R. Flury, Anne E. Jaskot, Harry C. Ferguson, Gábor Worseck, Kirill Makan, et al.. The Low-redshift Lyman Continuum Survey. I. New, Diverse Local Lyman Continuum Emitters. The Astrophysical Journal Supplement Series, 2022, 260, ⟨10.3847/1538-4365/ac5331⟩. ⟨insu-03711520⟩