4. Given two objects with intensity of brightness /1 and 12, a magnitude difference which is based on the ratio of their intensities can be defined, i.e., M1 - M2 = -2.5log10(7;), where M, and M2 are magnitudes. A galaxy with a mass of 5.7 x 10"0 M has an absolute magnitude of -17.3 at a distance of 29 Mpc. The absolute magnitude of the Sun is 4.83. Determine the mass-to-light ratio of the galaxy in solar units. Note that intensity is related to Luminosity by I =