The Spectral Evolution of the First Galaxies. Ii. Spectral Signatures of Lyman Continuum Leakage From Galaxies in the Reionization Epoch
Year: 2013
Type: article
Abstract: The fraction of ionizing photons that escape ( f 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 esc for individual galaxies at these epochs. We argue that since f esc regulates the impact of nebular emission on the spectra of galaxies, it should nonetheless be possible to indirectly probe f 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 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 1500 ≲ −16.0 galaxies at z ≈ 7 and for M 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 this effect.
Source: The Astrophysical Journal
Authors: Erik Zackrisson, Akio K. Inoue, Hannes Jensen
Institutions: Stockholm University, AlbaNova, Osaka Sangyo University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2092066132