Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-10-31
Astrophys.J. 599 (2003) L1-L4
Astronomy and Astrophysics
Astrophysics
4 pages, 3 figures, accepted by ApJL
Scientific paper
10.1086/381140
We use a high-resolution cosmological simulation to predict the distribution of HI Ly-alpha emission from the low-redshift (z<0.5) intergalactic medium (IGM). Our simulation can be used to reliably compute the emission from optically thin regions of the IGM but not that of self-shielded gas. We therefore consider several models that bracket the expected emission from self-shielded regions. Most galaxies are surrounded by extended (>10^2 kpc) ``coronae'' of optically thin gas with Ly-alpha surface brightness close to the expected background. Most of these regions contain smaller cores of dense, cool gas. Unless self-shielded gas is able to cool to T<10^4.1 K, these cores are much brighter than the background. The Ly-alpha coronae represent ``cooling flows'' of IGM gas accreting onto galaxies. We also estimate the number of Ly-alpha photons produced through the reprocessing of stellar ionizing radiation in the interstellar medium of galaxies; while this mechanism is responsible for the brightest Ly-alpha emission, it occurs on small physical scales and can be separated using high-resolution observations. In all cases, we find that Ly-alpha emitters are numerous (with a space density ~0.1 h^3 Mpc^-3) and closely trace the filamentary structure of the IGM, providing a new way to map gas inside the cosmic web.
Furlanetto Steven
Hernquist Lars
Schaye Joop
Springel Volker
No associations
LandOfFree
Mapping the Cosmic Web with Ly-alpha Emission 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 Mapping the Cosmic Web with Ly-alpha Emission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mapping the Cosmic Web with Ly-alpha Emission will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-417814