The Nature and Origin of the Non-Void Lyman alpha Cloud Population

Details The Nature and Origin of the Non-Void Lyman alpha Cloud Population The Nature and Origin of the Non-Void Lyman alpha Cloud Population

2003-08-22

arxiv.org/abs/astro-ph/0308390v1

Astrophys.J.595:19-28,2003

Astronomy and Astrophysics

Astrophysics

10 pages, 6 figures, ApJ 595 n1, in press

Scientific paper

10.1086/377350

I continue my study of the low-z Lyman alpha cloud population. Previously I showed how galaxy catalogs are used to attribute relative degrees of isolation to those clouds found in HST/GHRS spectra. I find that there exist two distinct populations corresponding to two distinct environments, variously characterized as void (unshocked) and non-void (shocked). Void clouds have a steep equivalent width distribution (i.e., many smaller absorbers) while non-void clouds have a flat distribution. These environment-specific observations of LyA clouds show that the predictions from N-body/hydro simulations are incorrect. Simulations fail to predict the existence of significant numbers of detectable void clouds. They incorrectly predict the characteristics of non-void clouds. Implicated in this failure is the so-called fluctuating Gunn-Peterson Approximation (FGPA) which envisions that LyA absorbers are formed in the large-scale structures of coalescing matter. I recently modeled the void cloud population as sub-galactic perturbations that have expanded in response to reionization. However, the success in this modeling was contingent upon using the more massive isothermal halo in place of the standard Navarro, Frenk & White. Here, I extend my modeling to non-void LyA clouds using the same basic cloud model. Nonvoid clouds were once unshocked, but when entering nonvoid space, they are shock stripped. By analytically stripping model void clouds, a good fit of the model CDS to observations is found if cloud velocities are ~100 km/s. Nonvoid clouds show strong concentration around galaxies, suggesting that the compact HVC population are members of this population.

Affiliated with

Also associated with

No associations

Rating

The Nature and Origin of the Non-Void Lyman alpha Cloud Population 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 Nature and Origin of the Non-Void Lyman alpha Cloud Population, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Nature and Origin of the Non-Void Lyman alpha Cloud Population will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-385849