14
Black Holes – detection
–
•By definition – can’t see light from black hole itself
•
•Can see large amounts of energy released by falling material just before it crosses RS
•
•Can see motion of nearby objects caused by gravity of black hole
•
•Example: Like White Dwarf accretion disk but w/ black hole instead
–Gas from red giant companion spills over towards black hole
–Gas spirals in toward black hole, through accretion disk
•Gas will be much hotter because it falls further, to very small RS
–Gas will be moving at very high velocity
•Much faster than with white dwarf since much closer  (P2 µ a3)
•
•Signature of black hole:  Very high energy release, very high velocity
–
•We will find MASSIVE black holes in centers of most galaxies