Suppose the mass distribution of an elliptical galaxy is sph

Suppose the mass distribution of an elliptical galaxy is spherically symmetric, and it\'s density profile is given by:

to a factor of 2.

Solution

a) M(r)= (4₀r_s²)r

this gives R_e=0.5r_s

b)1/2

U=-G(4₀r_s²)²r_s (Integrate using shell elements)

_{Comparing we have alpha=.5.}