A new technique for finding galaxies leaking Lyman-continuum radiation: [SII]-deficiency
| العنوان: | A new technique for finding galaxies leaking Lyman-continuum radiation: [SII]-deficiency |
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| المؤلفون: | Bingjie Wang, Rachel Alexandroff, Claus Leitherer, Roderik Overzier, Sanchayeeta Borthakur, Timothy M. Heckman |
| سنة النشر: | 2019 |
| مصطلحات موضوعية: | Physics, Star formation, Continuum radiation, FOS: Physical sciences, Astronomy and Astrophysics, Extragalactic astronomy, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Interstellar medium, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Intergalactic medium, Galaxy formation and evolution, Astrophysics::Galaxy Astrophysics |
| الوصف: | The source responsible for the reionization of the Universe is believed to be the population of star-forming galaxies at $z\sim6$ to 12. The biggest uncertainty concerns the fraction of Lyman-continuum photons that actually escape from the galaxies. In recent years, several relatively small samples of "leaky" galaxies have been uncovered, and clues have begun to emerge as to both the indirect signposts of leakiness and of the conditions/processes that enable the escape of ionizing radiation. In this paper we present the results of a pilot program aimed to test a new technique for finding leaky galaxies---using the weakness of the [SII] nebular emission-lines relative to typical star-forming galaxies as evidence that the interstellar medium is optically-thin to the Lyman continuum. We use the Cosmic Origins Spectrograph on the Hubble Space Telescope to detect significant emerging flux below the Lyman edge in two out of three [SII]-weak star-forming galaxies at $z\sim0.3$. We show that these galaxies differ markedly in their properties from the class of leaky "Green-Pea" galaxies at similar redshifts: our sample galaxies are more massive, more metal-rich, and less extreme in terms of their stellar population and the ionization state of the interstellar medium. Like the Green Peas, they have exceptionally high star-formation rates per unit area. They also share some properties with the known leaky galaxies at $z\sim3$, but are significantly dustier. Our results validate a new way to identify local laboratories for exploring the processes that made it possible for galaxies to reionize the Universe. Accepted for publication in ApJ. 17 pages, 8 figures, 8 tables |
| اللغة: | English |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::858bc903d636cd97c53573c9088dfd4e http://arxiv.org/abs/1909.01368 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....858bc903d636cd97c53573c9088dfd4e |
| قاعدة البيانات: | OpenAIRE |
| الوصف غير متاح. |