skip to main content

Title: THE SPECTRAL EVOLUTION OF THE FIRST GALAXIES. II. SPECTRAL SIGNATURES OF LYMAN CONTINUUM LEAKAGE FROM GALAXIES IN THE REIONIZATION EPOCH

The fraction of ionizing photons that escape (f{sub esc}) from z ∼> 6 galaxies is an important parameter for assessing the role of these objects in the reionization of the universe, but the opacity of the intergalactic medium precludes a direct measurement of f{sub esc} for individual galaxies at these epochs. We argue that since f{sub esc} regulates the impact of nebular emission on the spectra of galaxies, it should nonetheless be possible to indirectly probe f{sub esc} well into the reionization epoch. As a first step, we demonstrate that by combining measurements of the rest-frame UV slope β with the equivalent width of the Hβ emission line, galaxies with very high Lyman continuum escape fractions (f{sub esc} ≥ 0.5) should be identifiable up to z ≈ 9 through spectroscopy with the upcoming James Webb Space Telescope (JWST). By targeting strongly lensed galaxies behind low-redshift galaxy clusters, JWST spectra of sufficiently good quality can be obtained for M{sub 1500} ∼< –16.0 galaxies at z ≈ 7 and for M{sub 1500} ∼< –17.5 galaxies at z ≈ 9. Dust-obscured star formation may complicate the analysis, but supporting observations with ALMA or the planned SPICA mission may provide useful constraints on thismore » effect.« less
Authors:
;  [1] ;  [2]
  1. The Oskar Klein Centre, Department of Astronomy, AlbaNova, Stockholm University, SE-106 91 Stockholm (Sweden)
  2. College of General Education, Osaka Sangyo University, 3-1-1, Nakagaito, Daito, Osaka 574-8530 (Japan)
Publication Date:
OSTI Identifier:
22270679
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 777; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; GALAXIES; GALAXY CLUSTERS; INTERGALACTIC SPACE; IONIZATION; LIMITING VALUES; LYMAN LINES; OPACITY; PHOTONS; RED SHIFT; STARS; TELESCOPES; UNIVERSE