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Is the cosmic UV background fluctuating at redshift z ~ 6 ?

Jiren Liu·Hongguang Bi·Long-Long Feng·Li-Zhi Fang
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Abstract

We study the Gunn-Peterson effect of the photo-ionized intergalactic medium(IGM) in the redshift range 5< z <6.4 using semi-analytic simulations based on the lognormal model. Assuming a rapidly evolved and spatially uniform ionizing background, the simulation can produce all the observed abnormal statistical features near redshift z ~ 6. They include: 1) rapidly increase of absorption depths; 2) large scatter in the optical depths; 3) long-tailed distributions of transmitted flux and 4) long dark gaps in spectra. These abnormal features are mainly due to rare events, which correspond to the long-tailed probability distribution of the IGM density field, and therefore, they may not imply significantly spatial fluctuations in the UV ionizing background at z ~ 6.

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Jiren Liu, Hongguang Bi, Long-Long Feng, Li-Zhi Fang. 2006-05-24. Is the cosmic UV background fluctuating at redshift z ~ 6 ?. https://doi.org/10.1086/506149

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