Lyman alpha and Lyman continuum emission of Mg II-selected star-forming galaxies
- We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of seven compact low-mass star-forming galaxies at redshifts, z, in the range 0.3161-0.4276, with various O3Mg2 = [O III] lambda 5007/Mg II lambda 2796+2803 and Mg-2 = Mg II lambda 2796/Mg II lambda 2803 emission-line ratios. We aim to study the dependence of leaking Lyman continuum (LyC) emission on the characteristics of Mg ii emission together with the dependencies on other indirect indicators of escaping ionizing radiation. LyC emission with escape fractions f(esc)(LyC) = 3.1-4.6 per cent is detected in four galaxies, whereas only 1 sigma upper limits of f(esc)(LyC) in the remaining three galaxies were derived. A strong narrow Ly alpha emission line with two peaks separated by V-sep similar to 298-592 km s(-1) was observed in four galaxies with detected LyC emission and very weak Ly alpha emission is observed in galaxies with LyC non-detections. Our new data confirm the tight anticorrelation between f(esc)(LyC) and V-sep found forWe present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of seven compact low-mass star-forming galaxies at redshifts, z, in the range 0.3161-0.4276, with various O3Mg2 = [O III] lambda 5007/Mg II lambda 2796+2803 and Mg-2 = Mg II lambda 2796/Mg II lambda 2803 emission-line ratios. We aim to study the dependence of leaking Lyman continuum (LyC) emission on the characteristics of Mg ii emission together with the dependencies on other indirect indicators of escaping ionizing radiation. LyC emission with escape fractions f(esc)(LyC) = 3.1-4.6 per cent is detected in four galaxies, whereas only 1 sigma upper limits of f(esc)(LyC) in the remaining three galaxies were derived. A strong narrow Ly alpha emission line with two peaks separated by V-sep similar to 298-592 km s(-1) was observed in four galaxies with detected LyC emission and very weak Ly alpha emission is observed in galaxies with LyC non-detections. Our new data confirm the tight anticorrelation between f(esc)(LyC) and V-sep found for previous low-redshift galaxy samples. V-sep remains the best indirect indicator of LyC leakage among all considered indicators. It is found that escaping LyC emission is detected predominantly in galaxies with Mg-2 greater than or similar to 1.3. A tendency of an increase of f(esc)(LyC) with increasing of both the O3Mg2 and Mg-2 is possibly present. However, there is substantial scatter in these relations not allowing their use for reliable prediction of f(esc)(LyC).…
Author details: | Yuri I. IzotovORCiD, John ChisholmORCiD, Gábor WorseckORCiD, Natalia G. Guseva, Daniel SchaererORCiD, Jason Xavier ProchaskaORCiD |
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DOI: | https://doi.org/10.1093/mnras/stac1899 |
ISSN: | 0035-8711 |
ISSN: | 1365-2966 |
Title of parent work (English): | Monthly notices of the Royal Astronomical Society |
Publisher: | Oxford University Press |
Place of publishing: | Oxford |
Publication type: | Article |
Language: | English |
Date of first publication: | 2022/07/22 |
Publication year: | 2022 |
Release date: | 2024/06/25 |
Tag: | dark ages; first stars; galaxies: ISM; galaxies: abundances; galaxies: dwarf; galaxies: fundamental parameters; galaxies: starburst; reionization |
Volume: | 515 |
Issue: | 2 |
Number of pages: | 18 |
First page: | 2864 |
Last Page: | 2881 |
Funding institution: | NASA from the Space Telescope Science Institute [HST-GO-15845]; NASA; [NAS 5-26555]; National Academy of Sciences of Ukraine [0122U002259];; Alfred P. Sloan Foundation; National Science Foundation; U.S. Department; of Energy Office of Science; National Aeronautics and Space; Administration |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
Peer review: | Referiert |
Publishing method: | Open Access / Bronze Open-Access |
License (German): | Keine öffentliche Lizenz: Unter Urheberrechtsschutz |