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D.3 Disk Profile
For , Equation D.1 can be rewritten as the exponential law
|
(D.10) |
which characterizes the profile of disk components of disk galaxies, where
is the central surface brightness and is referred to as the
disk scale length. The relations between these two quantities and
and are respectively
|
(D.11) |
According to this profile, the total brightness of the galaxy can be written as
|
(D.12) |
while the average surface brightness inside the effective radius
is related to by
|
(D.13) |
When put on a magnitude scale, the disk profile given by
Equation D.10 becomes
|
(D.14) |
while equalling Equations A.4 and D.12, one
obtain for the expression
|
(D.15) |
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Up: D. Galaxy Surface Brightness
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Mattia Vaccari
2000-12-05