Is the cosmic UV background fluctuating at redshift z ~ 6 ?
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.
Keywords
Cite
@article{arxiv.astro-ph/0605614,
title = {Is the cosmic UV background fluctuating at redshift z ~ 6 ?},
author = {Jiren Liu and Hongguang Bi and Long-Long Feng and Li-Zhi Fang},
journal= {arXiv preprint arXiv:astro-ph/0605614},
year = {2009}
}
Comments
12 pages, 4 figs, accepted by ApJL