| Models of Elliptical Galaxies |
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| • | Should
follow equations of stellar dynamics. |
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| • | Treat
as “collisionless” ensemble |
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| • | Relaxation
time is important – this defines the |
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| time
between “collisions” |
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| • | Work
out energetically to get |
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| • | Trelax = V3/8πnG2m2log(R/b) |
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| • | V
is mean relative speed, n is stellar density, m |
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| is
the mean stellar mass, R is radius of galaxy, |
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| and
b is the minimum impact parameter. |
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| • | Details
will probably be a homework problem. |
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