Improved Constraints on the Neutral Intergalactic Hydrogen surrounding Quasars at Redshifts z > 6
Abstract
We analyze the evolution of H II regions around the seven known SDSS quasars at z>6. The comparison between the observed and model radii of the H II regions generated by these quasars individually suggests that the surrounding intergalactic hydrogen is significantly neutral. When all constraints are combined, the existing quasar sample implies a volume-averaged neutral fraction that is larger than 10% at z>6. This limited sample permits a preliminary analysis of the correlations between the quasar parameters, the sizes of their H II regions, and the associated constraints on the neutral hydrogen fraction. We find no evidence in these correlations to contradict the interpretation that the red side of the Gunn-Peterson trough corresponds to the boundary between an H II region and a partially neutral IGM.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2005
- DOI:
- 10.1086/430874
- arXiv:
- arXiv:astro-ph/0411625
- Bibcode:
- 2005ApJ...628..575W
- Keywords:
-
- Cosmology: Theory;
- Galaxies: Formation;
- Galaxies: Intergalactic Medium;
- Astrophysics
- E-Print:
- 9 pages, 4 figures. Submitted to ApJ