Figure: Examples of galaxies of various surface brightness. At top left
is the Messier object M51, a typical high surface brightness spiral galaxy. To its
right is UGC 12522, a galaxy with a bright central core yet faint (
(0)
= 23.1 mag arcsec
) spiral
arms. On the bottom left is C9-1, which, with its amorphous shape is a typical LSB galaxy
(
(0) = 23.9 mag arcsec
).
Finally, on the bottom right is P2-4, a galaxy which could not
have been detected without a low noise detector (in this case a 2048 x 2048 CCD) and which
appears to be composed of loosely connected blobs
(0) = 25.5
mag arcsec
).