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Title: On modeling and measuring the temperature of the z ∼ 5 intergalactic medium

The temperature of the low-density intergalactic medium (IGM) at high redshift is sensitive to the timing and nature of hydrogen and He II reionization, and can be measured from Lyman-alpha (Lyα) forest absorption spectra. Since the memory of intergalactic gas to heating during reionization gradually fades, measurements as close as possible to reionization are desirable. In addition, measuring the IGM temperature at sufficiently high redshifts should help to isolate the effects of hydrogen reionization since He II reionization starts later, at lower redshift. Motivated by this, we model the IGM temperature at z ≳ 5 using semi-numeric models of patchy reionization. We construct mock Lyα forest spectra from these models and consider their observable implications. We find that the small-scale structure in the Lyα forest is sensitive to the temperature of the IGM even at redshifts where the average absorption in the forest is as high as 90%. We forecast the accuracy at which the z ≳ 5 IGM temperature can be measured using existing samples of high resolution quasar spectra, and find that interesting constraints are possible. For example, an early reionization model in which reionization ends at z ∼ 10 should be distinguishable—at high statistical significance—from a lowermore » redshift model where reionization completes at z ∼ 6. We discuss improvements to our modeling that may be required to robustly interpret future measurements.« less
Authors:
;  [1]
  1. Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States)
Publication Date:
OSTI Identifier:
22356556
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 788; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ABSORPTION SPECTRA; ACCURACY; DENSITY; HYDROGEN; INTERGALACTIC SPACE; LIMITING VALUES; LYMAN LINES; QUASARS; RED SHIFT; RESOLUTION; SIMULATION; UNIVERSE