Testing an indirect method for identifying galaxies with high levels of Lyman continuum leakage

Satoshi Yamanaka, Akio K. Inoue, Toru Yamada, Erik Zackrisson, Ikuru Iwata, Genoveva Micheva, Ken Mawatari, Takuya Hashimoto, Mariko Kubo

Research output: Contribution to journalArticlepeer-review


Using a sample of galaxies at z ≈ 3 with detected Lyman Continuum (LyC) leakage in the SSA22 field, we attempt to verify a proposed indirect method for identifying cases with high LyC escape fraction fesc based on measurements of the Hβ equivalent width (EW) and the β slope of the UV continuum. To this end, we present Keck/MOSFIRE Hβ emission line flux measurements of LyC galaxies (LCGs) at spectroscopic redshifts zspec ∼ 3.3, Lyman break galaxies (LBGs) at photometric redshifts zphot = 2.7-3.7, and Lyα emitters at zphot = 3.1. We also reconfirm the spectroscopic redshifts and measure the Hβ emission line fluxes from 2 LCGs and 6 LBGs. For the LCG in our sample with the most extreme fesc, as revealed by the direct detection of LyC photons, we find that the EW(Hβ)-β method gives a broadly consistent estimate for fesc, although the error bars remain very large. We also discuss how a combination of fesc measurements based on direct and indirect methods can shed light on the LyC escape mechanism and the anisotropy of the leakage.

Original languageEnglish
JournalUnknown Journal
Publication statusPublished - 2020 Mar 8


  • Galaxies: high-redshift
  • Galaxies: ISM
  • Galaxies: starburst

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Testing an indirect method for identifying galaxies with high levels of Lyman continuum leakage'. Together they form a unique fingerprint.

Cite this