Radiative Transfer Effect on Ultraviolet Pumping of the 21cm Line in the High Redshift Universe

Details Radiative Transfer Effect on Ultraviolet Pumping of the 21cm Line in the High Redshift Universe Radiative Transfer Effect on Ultraviolet Pumping of the 21cm Line in the High Redshift Universe

2007-06-06

arxiv.org/abs/0706.0895v1

Astronomy and Astrophysics

Astrophysics

7 pages, 4 figures, submitted to ApJ

Scientific paper

10.1086/522491

During the epoch of reionization the 21cm signal is sensitive to the scattering rate of the ultraviolet photons, redshifting across the Lyman_alpha resonance. Here we calculate the photon scattering rate profile for a single ultraviolet source. After taking into account previously neglected natural broadening of the resonance line, we find that photons approach the resonance frequency and experience most scatterings at a significantly smaller distance from the source than naively expected r=(dnu/nu_0)(c/H), where dnu=nu-nu_0 is the initial frequency offset, and the discrepancy increases as the initial frequency offset decreases. As a consequence, the scattering rate P(r) drops much faster with increasing distance than the previously assumed 1/r^2 profile. Near the source (r<1Mpc comoving), the scattering rate of photons that redshift into the Ly_alpha resonance converges to P(r) \propto r^{-7/3}. The scattering rate of Ly_alpha photons produced by splitting of photons that redshift into a higher resonance (Ly_gamma, Ly_delta, etc.) is only weakly affected by the radiative transfer, while the sum of scattering rates of Ly_alpha photons produced from all higher resonances also converges to P(r) \propto r^{-7/3} near the source. At 15

Affiliated with

Also associated with

No associations

Rating

Radiative Transfer Effect on Ultraviolet Pumping of the 21cm Line in the High Redshift Universe 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 Radiative Transfer Effect on Ultraviolet Pumping of the 21cm Line in the High Redshift Universe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radiative Transfer Effect on Ultraviolet Pumping of the 21cm Line in the High Redshift Universe will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-441547