A quasar with an observed luminosity of L = 1012 L is shining at the Eddington limit, with a net efficiency of 10%.
What is the mass accretion rate (in units of Mo year -1)?
The mass accretion rate can be calculated using the equation:
M_acc = (L/LEdd) * (4πGM/c) = (1012 L/1.3 x 1038 erg/s) * (4πG(2 x 1030 kg) / 3 x 108 m/s) = 1.2 x 10-6 Mo year-1.