| Galaxy Masses |
|
|
|
|
|
|
|
|
|
|
|
| • | Virial
Theorem: A relationship between |
|||||||||
| gravitational
potential energy and |
||||||||||
| velocities
for a dynamically relaxed and |
||||||||||
| bound
system. |
||||||||||
| • | T
= ½ |U|, where T is the total kinetic |
|||||||||
| energy
and U is the potential energy. |
||||||||||
| • | So,
for a cluster of stars or a cluster of |
|||||||||
| galaxies,
measuring T (by measuring |
||||||||||
| velocities)
can give U and therefore M. |
||||||||||
