X For Andromeda . ... Like the Milky Way , Andromeda's galactic center appears to harbor an X-ray source characteristic of a black hole of a million or more solar masses. ... While the X-rays are produced as material falls into the black hole and heats up, estimates from the X-ray data show Andromeda's central source to be surprisingly cool - only a million degrees or so compared to the tens of millions of degrees indicated for Andromeda's X-ray binaries . ... NASA Official: Jay Norris. ...