Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994mnras.266..343m&link_type=abstract
Monthly Notices of the Royal Astronomical Society, Vol. Vol. 266, No. 2, p. 343 - 352
Astronomy and Astrophysics
Astronomy
118
Intergalactic Gas: Heating, Intergalactic Gas: Photoionization, Intergalactic Gas: Quasars, Intergalactic Gas: Thermal Evolution, Intergalactic Gas: Uv Radiation, Intergalactic Matter: Cosmology
Scientific paper
In most models of the reionization of the intergalactic medium, sources of UV radiation create ionized regions around them which expand until they overlap. The gas is impulsively heated when it enters one of these ionized regions. The authors discuss the various physical effects that determine the temperature of the gas after the passage of the ionization front. Sources with different spectra may heat the surrounding gas to different temperatures, creating large-scale inhomogeneities of the gas temperature in the Universe. The presence of helium is particularly important, since it allows the post-reionization temperature to reach values as high as ˜5×104K. Subsequent adiabatic heating as gas collapses into haloes can raise the temperature even more, explaining large b-parameters in Ly α clouds in the minihalo model.
The gas heated in this way retains memory of the initial temperature and the reheating epoch, since the thermal time-scale is long. Ly α absorption lines of low column density, which arise in the non-virialized outer parts of haloes with overdensity less than ˜10, could show a spatial correlation caused by variations in the initial temperature. The authors also investigate the modifications of the proximity effect produced by the different equilibrium temperature of the gas in the vicinity of a quasar. This new proximity effect could also cause the lines close to the emitting quasar to have a different distribution of b-parameters.
Miralda-Escude' Jordi
Rees Martin J.
No associations
LandOfFree
Reionization and thermal evolution of a photoionized intergalactic medium. 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 Reionization and thermal evolution of a photoionized intergalactic medium., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reionization and thermal evolution of a photoionized intergalactic medium. will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1681618