The distant quasar ULAS J1120+0641 has a mass 2 × 10⁹ M_e. Assuming it is at its Eddington limit, what is its luminosity (in solar luminosities)? A)30,000 B)2 x 10⁶ C)6 x 10⁹ D)6 x 10¹³

Question

Quizplus · Accepted Answer

The Eddington luminosity is given by:$$L_{Edd}=\frac{4\pi GMm_p c}{\sigma_T}$$where:* G is the gravitational constant* M is the mass of the object* m_p is the mass of a proton* c is the speed of light* σ_T is the Thomson scattering cross-sectionPlugging in the given values, we get:$$L_{Edd}=\frac{4\pi (6.674	imes10^{-11}	ext{ m}^3	ext{/kg s}^2)(2	imes10^9	ext{ M}_\odot)(1.673	imes10^{-27}	ext{ kg})(3	imes10^8	ext{ m/s})^2}{6.652	imes10^{-29}	ext{ m}^2}$$$$L_{Edd}=6	imes10^{13}L_\odot$$Therefore, the luminosity of the quasar is 6 x 10^13 solar luminosities.

The Distant Quasar ULAS J1120+0641 Has a Mass 2 ×