Hydrogen-ionizing photon production rate
= Hydrogen-ionizing photon production rate
{title2=$Q_{\rm H}$}
The hydrogen-ionizing photon production rate is the number of photons emitted per unit time above the hydrogen ionization threshold:
$$
Q_{\rm H}=\int_{\nu_0}^{\infty}\frac{L_\nu}{h\nu}\,d\nu.
$$