The Spectral Evolution of the First Galaxies. III. Simulated James Webb Space Telescope Spectra of Reionization-epoch Galaxies with Lyman-continuum Leakage

Erik Zackrisson, Christian Binggeli, Kristian Finlator, Nickolay Y. Gnedin, Jan Pieter Paardekooper, Ikkoh Shimizu, Akio K. Inoue, Hannes Jensen, Genoveva Micheva, Sadegh Khochfar, Claudio Dalla Vecchia

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20 Citations (Scopus)

Abstract

Using four different suites of cosmological simulations, we generate synthetic spectra for galaxies with different Lyman-continuum ESCape fractions (fESC) at redshifts z ≈ 7-9, in the rest-frame wavelength range relevant for the James Webb Space TelESCope (JWST) NIRSpec instrument. By investigating the effects of realistic star formation histories and metallicity distributions on the EW(Hβ)-β diagram (previously proposed as a tool for identifying galaxies with very high fESC), we find that neither of these effects are likely to jeopardize the identification of galaxies with extreme Lyman-continuum leakage. Based on our models, we expect that essentially all z ≈ 7-9 galaxies that exhibit rest-frame EW(Hβ) ≲ 30 Å to have fESC > 0.5.. Incorrect assumptions concerning the ionizing fluxes of stellar populations or the dust properties of z > 6 galaxies can in principle bias the selection, but substantial model deficiencies of this type should at the same time be evident from offsets in the observed distribution of z > 6 galaxies in the EW(Hβ)-β diagram compared to the simulated distribution. Such offsets would thereby allow JWST/NIRSpec measurements of these observables to serve as input for further model refinement.

Original languageEnglish
Article number78
JournalAstrophysical Journal
Volume836
Issue number1
DOIs
Publication statusPublished - 2017 Feb 10

Keywords

  • dark ages, reionization, first stars
  • galaxies: high-redshift
  • techniques: spectroscopic

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Zackrisson, E., Binggeli, C., Finlator, K., Gnedin, N. Y., Paardekooper, J. P., Shimizu, I., Inoue, A. K., Jensen, H., Micheva, G., Khochfar, S., & Vecchia, C. D. (2017). The Spectral Evolution of the First Galaxies. III. Simulated James Webb Space Telescope Spectra of Reionization-epoch Galaxies with Lyman-continuum Leakage. Astrophysical Journal, 836(1), [78]. https://doi.org/10.3847/1538-4357/836/1/78