The morphology of HII regions during reionization

Details The morphology of HII regions during reionization The morphology of HII regions during reionization

2006-10-04

arxiv.org/abs/astro-ph/0610094v3

Mon.Not.Roy.Astron.Soc.377:1043-1063,2007

Astronomy and Astrophysics

Astrophysics

23 pages, 18 figures

Scientific paper

10.1111/j.1365-2966.2007.11489.x

It is possible that the properties of HII regions during reionization depend sensitively on many poorly constrained quantities (the nature of the ionizing sources, the clumpiness of the gas in the IGM, the degree to which photo-ionizing feedback suppresses the abundance of low mass galaxies, etc.), making it extremely difficult to interpret upcoming observations of this epoch. We demonstrate that the actual situation is more encouraging, using a suite of radiative transfer simulations, post-processed on outputs from a 1024^3, 94 Mpc N-body simulation. Analytic prescriptions are used to incorporate small-scale structures that affect reionization, yet remain unresolved in the N-body simulation. We show that the morphology of the HII regions is most dependent on the global ionization fraction x_i. This is not to say that the bubble morphology is completely independent of all parameters besides x_i. The next most important dependence is that of the nature of the ionizing sources. The rarer the sources, the larger and more spherical the HII regions become. The typical bubble size can vary by as much as a factor of 4 at fixed x_i between different possible source prescriptions. The final relevant factor is the abundance of minihalos or of Lyman-limit systems. These systems suppress the largest bubbles from growing, and the magnitude of this suppression depends on the thermal history of the gas as well as the rate at which minihalos are photo-evaporated. We find that neither source suppression owing to photo-heating nor gas clumping significantly affect the large-scale structure of the HII regions. We discuss how observations of the 21cm line with MWA and LOFAR can constrain properties of reionization, and we study the effect patchy reionization has on the statistics of Lyman-alpha emitting galaxies. [abridged]

Affiliated with

Also associated with

No associations

Rating

The morphology of HII regions during reionization does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The morphology of HII regions during reionization, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The morphology of HII regions during reionization will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-155230