Cosmic reionization on computers. II. Reionization history and its back-reaction on early galaxies

Journal Article · Sat Sep 20 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/793/1/30· OSTI ID:22365031

Gnedin, Nickolay Y. ^[1]

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1. Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

We compare the results from several sets of cosmological simulations of cosmic reionization, produced under the Cosmic Reionization On Computers project, with existing observational data on the high-redshift Lyα forest and the abundance of Lyα emitters. We find good consistency with the observational measurements and previous simulation work. By virtue of having several independent realizations for each set of numerical parameters, we are able to explore the effect of cosmic variance on observable quantities. One unexpected conclusion we are forced into is that cosmic variance is unusually large at z > 6, with both our simulations and, most likely, observational measurements still not fully converged for even such basic quantities as the average Gunn-Peterson optical depth or the volume-weighted neutral fraction. We also find that reionization has little effect on the early galaxies or on global cosmic star formation history, because galaxies whose gas content is affected by photoionization contain no molecular (i.e., star-forming) gas in the first place. In particular, measurements of the faint end of the galaxy luminosity function by the James Webb Space Telescope are unlikely to provide a useful constraint on reionization.

• OSTI ID: 22365031
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 793; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
COSMOLOGY
GALAXIES
IONIZATION
LIMITING VALUES
LUMINOSITY
LYMAN LINES
PHOTOIONIZATION
RED SHIFT
SPACE
STAR EVOLUTION
STARS
TELESCOPES
UNIVERSE
WEIGHT