Lyman continuum escape fraction in Ly α emitters at z ? 3.1

Fuyan Bian, Xiaohui Fan

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

We measure the Lyman continuum (LyC) escape fraction in 54 faint Lyman-alpha emitters (LAEs) at $z$ ? 3.1 in the GOODS-South field. With the average magnitude of R = 26.7 AB (MUV = -18.8 and L ? 0.1L∗), these galaxies represent a population of compact young dwarf galaxies. Their properties are likely to resemble those in the galaxies responsible for reionizing the Universe at $z$ > 6. We do not detect LyC emission in any individual LAEs in the deep HST F336W images, which covers the rest-frame 820 Å. We do not detect the LyC emission of these LAEs in the stacked F336W images either. The 3σ upper limit of LyC escape fractions is $f-{\rm esc}\lt 14\!-\!32{{\ \rm per\ cent}}$. However, the high Ly α rest-frame equivalent width (EW), low stellar mass, and UV luminosity of these LAEs suggest that they should have $f-{\rm esc}\gt 50{{\ \rm per\ cent}}$. The low LyC escape fraction from this work and other stacking analyses suggests that the LyC-leaking galaxies with $f-{\rm esc}\gt 50{{\ \rm per\ cent}}$ at $z$ = 2-3 do not follow the relation between fesc and UV luminosity and Ly α EW derived from typical galaxies at similar redshifts. Therefore, the UV luminosity and Ly α EW are not the best indicators for the LyC escape fraction.

Original languageEnglish (US)
Pages (from-to)L65-L69
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume493
Issue number1
DOIs
StatePublished - Jan 28 2020

Keywords

  • cosmology: dark ages, reionization, first stars
  • galaxies: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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