darkhistory.physics.CMB_spec¶
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darkhistory.physics.
CMB_spec
(eng, temp)¶ CMB spectrum in number of photons cm-3 eV-1.
The normalization used here is
\[\frac{dN}{dE \, dV} = \frac{E^2}{\pi^2 (\hbar c)^3} \frac{1}{e^{E/T_\text{CMB}} - 1} \,,\]with TCMB given in eV. Returns zero if E > 500 TCMB.
Parameters: - temp : float
Temperature of the CMB in eV.
- eng : float or ndarray
Energy of the photon in eV.
Returns: - ndarray
The number density of photons per unit energy in eV.