Low-redshift Lyman continuum leaking galaxies with high [O iii]/[O ii] ratios
| Autor: | Y. I. Izotov, Ivana Orlitova, N. G. Guseva, Daniel Schaerer, Gabor Worseck, Fricke Fricke, Trinh X. Thuan, Anne Verhamme |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Cosmic Origins Spectrograph Stellar mass 010308 nuclear & particles physics Doubly ionized oxygen FOS: Physical sciences Institut für Physik und Astronomie Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Astrophysics - Astrophysics of Galaxies 01 natural sciences Spectral line Galaxy Redshift Stars Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences ddc:520 Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Reionization Astrophysics::Galaxy Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society |
| ISSN: | 1365-2966 0035-8711 |
| DOI: | 10.1093/mnras/sty1378 |
| Popis: | We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of five star-forming galaxies at redshifts z in the range 0.2993-0.4317 and with high emission-line flux ratios O32=[OIII]5007/[OII]3727 ~ 8-27 aiming to detect the Lyman continuum (LyC) emission. We detect LyC emission in all galaxies with the escape fractions fesc(LyC) in a range of 2-72 per cent. A narrow Ly-alpha emission line with two peaks in four galaxies and with three peaks in one object is seen in medium-resolution COS spectra with a velocity separation between the peaks Vsep varying from ~153 km/s to ~345 km/s. We find a general increase of the LyC escape fraction with increasing O32 and decreasing stellar mass M*, but with a large scatter of fesc(LyC). A tight anti-correlation is found between fesc(LyC) and Vsep making Vsep a good parameter for the indirect determination of the LyC escape fraction. We argue that one possible source driving the escape of ionizing radiation is stellar winds and radiation from hot massive stars. Comment: 16 pages, 11 figures, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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