Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II Reionization

Details Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II Reionization Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II Reionization

2007-11-13

arxiv.org/abs/0711.1904v1

Astronomy and Astrophysics

Astrophysics

Scientific paper

We study the ionization and thermal evolution of the intergalactic medium during the epoch of \heii reionization by means of radiation hydrodynamical cosmological simulations. We post-process baryonic density fields from a standard optically-thin IGM simulation with a homogeneous galaxy-dominated UV background (UVB) which reionizes \hi and \hei at z=6.5 but does not have any contribution to the ionization of \heii. Quasars with luminosities proportional to the mass of the host halos are then introduced as point sources throughout the 100 Mpc simulation volume consistent with the Pei luminosity function. We evolve the spatial distribution of the \heii ionizing radiation field using a time-implicit variable tensor Eddington factor radiative transfer scheme. Simultaneously, we also solve for the local ionization of \heii to \heii and the associated photoheating of the gas. We find that the percolation of the \heiii regions is essentially complete by z=2.5. When comparing to a self-consistent optically thin simulation we find that in optically thick calculation the gas temperature is higher by a factor of approximately 1.7 at the mean gas density level. We use 300 random lines of sight to compute at $\bar{z} = 2.5 \pm 0.1$ a mean \heii \lya line transmission of $\bar{F} = 0.304 \pm 0.002$. We compare the broadening width of the \hi and \heii \lya lines to the results from the self-consistent optically thin simulation and find a shift by approximately 1.25 km/s of the b-parameter distribution. Estimating the relative broadening width between the two forests shows that the \heii median b-parameter is about 0.8 times the median \hi broadening width. This implies that the \heii absorbers are physically extended consistent with conclusions from observed lines of sight.

Affiliated with

Also associated with

No associations

Rating

Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II 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 Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II Reionization, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II Reionization will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-270130