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Cited by 321

The DOI matches its Crossref record; 69 of the 69 references it cites were found in a registry or an index.

New measurements of the ionizing ultraviolet background over 2 < z < 5 and implications for hydrogen reionization

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Becker, George D., Bolton, James S.·2013·Monthly Notices of the Royal Astronomical Society
DOI 10.1093/mnras/stt1610
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Abstract

We present new measurements of the intensity of the ionizing ultraviolet background and the global emissivity of ionizing photons over 2 < z < 5. Our results are based on a suite of updated measurements of physical properties of the high-redshift intergalactic medium (IGM), including gas temperatures and the opacity of the IGM to Ly-alpha and ionizing photons. Consistent with previous works, we find a relatively flat hydrogen photoionization rate over 2 < z < 5, although our measurements are roughly a factor of two higher than the 2008 values of Faucher-Giguere et al., due primarily to our lower gas temperatures. The ionizing emissivity we derive is also generally higher than other recent estimates due to a combination of lower gas temperatures, higher ionizing opacity, and an accounting of cosmological radiative transfer effects. We find evidence that the emissivity increases from z~3 to 5, reaching ~5 ionizing photons per atom per gigayear at z=4.75 for realistic galaxy spectra. We further find that galaxies must dominate the emissivity near 1 Ryd at z > 4, and possibly at all redshifts z > 2.4. Our results suggest that the globally-averaged ionizing "efficiency" of star-forming galaxies increases substantially with redshift over 3.2 < z < 4.75. This trend is consistent with the conclusion often drawn from reionization models that the ionizing efficiency of galaxies must be higher during reionization in order for galaxies to reionize the IGM by z=6. Our emissivity values at z~5 suggest that ionizing photons may have been a factor of two more abundant during the final stages of reionization than previously indicated. The evolution of the ionizing emissivity over 2 < z < 5 suggests, moreover, that the steep decline in the photoionization rate from z~5 to 6 may indicate a rapid evolution in the mean free path at z > 5.

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Metadata

Authors
Becker, G. D., & Bolton, J. S.
Venue
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Published
2013-10-16
Volume
436
Issue
2
Pages
1023-1039
ISSN
  • 0035-8711 (ISSN-L)
  • 1365-2966
DOI
10.1093/mnras/stt1610
OpenAlex
W1985198043
Cited by
321
References
69
FWCI
16.23
Type
journal article
Language
en
Open access
green

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CoChat. (2026). Citation check: New measurements of the ionizing ultraviolet background over 2 < z < 5 and implications for hydrogen reionization. https://app.cochat.ai/papers/10.1093/mnras/stt1610
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Becker, G. D., & Bolton, J. S. (2013). New measurements of the ionizing ultraviolet background over 2 < z < 5 and implications for hydrogen reionization. Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/stt1610

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