 From this data, they found an average velocity Vr of -188 ± 3 km/s and velocity dispersion of 9.2 ± 2.6 km/s.This gives a mass to light ratio of M/Lv of 21 solar units which implies that And II contains a significant amount of dark matter.Also in 1999, Côté, Oke, & Cohen used the Keck to measure the spectra of 42 red giants.