is a member of the Local Group of galaxies, and is an elliptical dwarf
galaxy of the type E2. It is a companion of the Great Andromeda Galaxy,
M32 was the first elliptical galaxy ever discovered and was discovered
by Le Gentil in 1749. Since then there have been more observations of
this galaxy. It is among the most investigated elliptical galaxies since
it is one of the closest brightest elliptical galaxies to us. Messier
who is famous for grouping the galaxies into a catalogue, first observed
this object in 1757, 8 years after it was first discovered. It appears
as a round, bright patch, and is situated south of the central region
of Andromeda, M31.
was first resolved into stars by Baade in 1944, when he also resolved
the nucleus of M31. It was Baade who recognized that the stars of M32
were population 2 stars.
to other images of M32:
Contents of the
The image is oriented
with the North being straight up in the image, East is to the left. The
major axis is located about 25 degrees east of north.
For cases of observation, M32 can be found in the constellation Pegasus,
near the hind feet of the horse.
40° 53' 01"
Million Light Years
million M solar
1 Solar mass = 1.99
X 10^30 kg
Although M32 is a
dwarf galaxy, it resembles a much larger elliptical galaxy. Therefore
there are beliefs that M32 was at one time a large elliptical galaxy,
but lost its outer stars to the Halo of Andromeda, in past encounters.
Proof for these encounters is suggested in the disturbed spiral pattern
M32 consist mainly
of old population 2 stars, which are red old stars that were formed near
the beginning of the universe. However, there seem to be intermediate
stars of heavier elements. These are typical population 1 stars, which
were formed later and are hotter, bluer and brighter stars. The presence
of these heavier intermediate stars may be responsible for the difference
in characteristics of M32 from other dwarf galaxies of comparable size.
M32 is a lot brighter than other dwarf galaxies and its apparent color
is not normally associated with its age.
The light profile of the galaxy is shown below. The light profile
is a plot of the brightness versus the radius of the galaxy (distance
from the center to the point in consideration). This of importance because
the light profile of an elliptical galaxy can be used to determine the
mass enclosed in an effective radius. The effective radius (re) is also
an effect of the galaxy light profile. The equation below shows a relationship
for the brightness and radius.
r = distance (radius)
re = effective radius
E(r) = Brightness at distance r
Ee =Brightness at the effective radius re
The main characteristics of an elliptical galaxy light profile are:
- The brightness
decreases with increasing radius
- The log of the
brightness is directly proportional to the (radius)^(1/4)
It's nucleus contains
about one-third of this mass
image above shows contour lines of M32, and clearly shows its elliptical
effective radius for bulges of spirals is between 0.5 to 5 kpc. The value
for this experiment is 0.22kpc which is slightly lower than the expected
radius. However, this is because the brightness of M32 peaks rapidly as
you move in toward the center. This phenomenon can be seen on the graph
of the brightness versus the radius. The more light that a galaxy gives
off, the heavier it is. This is without the effects of dark matter. Since
the brightness of M32 peaks off rapidly around the center we would expect
a lot of its mass to be enclosed in a small radius.
The above image was compiled from 15 raw images by Andrew Vache, taken
with a CCD camera mounted to the 16" Schmidt-Cassegrain telescope
in the Calvin College Observatory. All the observing was completed on
November 12, 2002 between 7:30PM and 8:30PM. Corresponding dark images
(images taken with the camera shutter closed) and flat images (images
taken of diffuse incandescent light through the telescope) were also taken
on November 12.
Each raw and dark image was taken with a 9.25 second exposure.
After aligning the raw images, and subtracting the dark and flat images
from the aligned image looked as it does above.
Further image processing using the computer program DS9 led to the image
below, with the light in the galaxy fit to a squared scale, showing the
actual structure of the ellipse. A "heat" filter led to the
Team: Joel Eigege and Andrew Vache