Accretion Power An astronomer is monitoring the activity in a pair of QSOs. Base
ID: 1595338 • Letter: A
Question
Accretion Power An astronomer is monitoring the activity in a pair of QSOs. Based on their respective redshifts, the astronomer determines that QSO B is at a distance from Earth three times greater than QSO A (i.e. ds = 3 times d_A)- Both QSOs have the same apparent brightness, i.e. flux. The astronomer also determines that QSO A is accreting mass onto its central black hole at a rate of Delta m/Delta t = 0.5 M_sun/year. What are the accretion rate (in M_sun/year) and luminosity (in Joules/sec) of QSO B?Explanation / Answer
we know, Intensity is inversly proportional to d.
so,
accreation rate of QSO_B = 9*QSO_A
= 9*0.5*Msun/year
= 4.5 M_sun/Year
luminosity = Energy radited/time
= 4.5*M_sun*c^2/year
= 4.5*1.99*10^30*(3*10^8)^2/(365*24*60*60)
= 2.55*10^40 J/s