Homework Sourseyou are observing an elliptical galaxy and find that that ha
you are observing an elliptical galaxy and find that that half-light radius of the Galaxy is 150kpc and the velocity dispersion of the stars is 250 km/s. what is the mass of the Galaxy? is there more or less than the mass of the Milky Way?
you are observing an elliptical galaxy and find that that half-light radius of the Galaxy is 150kpc and the velocity dispersion of the stars is 250 km/s. what is the mass of the Galaxy? is there more or less than the mass of the Milky Way?
you are observing an elliptical galaxy and find that that half-light radius of the Galaxy is 150kpc and the velocity dispersion of the stars is 250 km/s. what is the mass of the Galaxy? is there more or less than the mass of the Milky Way?
Solution
M(r) = 2*(sigma)^2 * (radius) / G
M(r) = 2*(250*10^3)^2 * 3.08*10^19 / (6.674*10^-11) = 5.768 * 10^40 kg
Mass of milky way = 2.982 * 10 ^ 42 kg
hence massof milky way is greater than the mass of this eleptic galaxy
