Leonid Chuzhoy and Paul R. Shapiro 2007 ApJ 655 843 doi:10.1086/510146
Leonid Chuzhoy1 and Paul R. Shapiro1
Show affiliationsDuring the epoch of reionization a large number of photons were produced with frequencies below the hydrogen Lyman limit. After redshifting into the closest resonance, these photons underwent multiple scatterings with atoms. We examine the effect of these scatterings on the temperature of the neutral intergalactic medium (IGM). Continuum photons, emitted between the Lyα and Lyγ frequencies, heat the gas after being redshifted into the H Lyα or D Lyβ resonance. By contrast, photons emitted between the Lyγ and Lyman limit frequencies produce effective cooling of the gas. Prior to reionization, the equilibrium temperature of ~100 K for hydrogen and helium atoms is set by these two competing processes. At the same time, Lyβ resonance photons thermally decouple deuterium from other species, raising its temperature as high as 104 K. Our results have important consequences for the cosmic 21 cm background and the entropy floor of the early IGM, which can affect star formation and reionization.
diffuse radiation; intergalactic medium; radiation mechanisms: general
Issue 2 (2007 February 1)
Received 2006 April 22, accepted for publication 2006 October 10
Leonid Chuzhoy and Paul R. Shapiro 2007 ApJ 655 843
Abhijit Biswas and P K Basu 2003 Semicond. Sci. Technol. 18 907
B Konopelchenko et al 2006 J. Phys. A: Math. Gen. 39 11231
Hannah Jang-Condell 2009 ApJ 700 820
Sean N. Raymond et al. 2010 ApJ 711 772
I Zivic and S Milosevic 1993 J. Phys. A: Math. Gen. 26 3393
Jason Glenn and Todd R. Hunter 2001 ApJS 135 177
C. A. Onken et al. 2003 ApJ 585 121
G Brown and J S Thorp 1967 Br. J. Appl. Phys. 18 1423
M L Garg et al 1985 J. Phys. B: At. Mol. Phys. 18 4529