- #1
utopiaNow
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Homework Statement
We are to assume the recombination happens at redshift [tex]z_{rec}[/tex] when the number density of photons [tex] n_{\gamma}(z_{rec}) [/tex] capable of ionizing hydrogen is exactly equal to the number density of baryons [tex] n_{b}(z_{rec}) [/tex]. Use the measured number density of baryons, the temperature of the CMB and the blackbody radiation to find out at what redshift [tex]z_{rec}[/tex] we have [tex] n_{\gamma}(z_{rec}) = n_{b}(z_{rec}). [/tex]
2. The attempt at a solution
Sorry I don't have time to write in detail what I have so far. But basically I come down to [tex] \Omega_{\gamma}E_{bary} \over hf_{mean}\Omega_{bary} [/tex] [tex]= 1 [/tex]
However this doesn't make use of blackbody radation, or the temperature of the CMB, if I'm supposed to equate [tex] \Omega_{\gamma} [/tex] to Temperature of the CMB, then I'm not sure how to do that step.
Thanks