M87
Giant Elliptical Galaxy, Matt Cosnek
The M87 galaxy, the
bright object on the middle left, is an enormous E1 elliptical galaxy
located at the center
of the Virgo Cluster, roughly 60 million light years
from us. Discovered by Charles Messier in 1781, M87 is
much larger than
our Milky Way galaxy. To compare the two, M87 contains about 15,000 globular
clusters,
while the Milky Way has only 150 to 200 globulars. M87 is also
about 2.7 trillion times the mass of the sun.
M87's size is due to the
fact that it has merged with so many other galaxies. A phenomenon known
as
galactic cannibalism. Also shown in the picture are galaxies NGC4486B
(type C galaxy located at top middle),
NGC4478 (E1 galaxy located at bottom
right), NGC4986A (type C galaxy located below M87), and NGC4476
(S0 galaxy
located at far right).
M87 is unique because
of a jet that extends from its center (Emphasized in the picture below).
The jet
extends for thousands of light years and consists of gas that
is shot out from a super-massive black hole at
M87's center.
The above Radio picture
shows the Radio lobes of M87. The radio lobes are approximately 80 kpc
from end
to end. The image below is a close up on the red area of the
Radio lobe picture. It shows the super massive
black hole at the center
and the jet extending from it.
The X-Ray image below
of M87's jet shows the synchrotron radiation, which is emitted by energetic
electrons spiraling around magnetic field lines.
The graph below is
a light profile of M87. The light profile shows the pixel brightness as
the radius increases
along the major axis of M87. The equation at the
top of the graph represents the portion from 18 to 30
[Radius (kpc)}^(1/4).
This can be used to find the effective radius of M87, 7.4 kpc with an
uncertainty of 158
pc. The effective radius represents the area where
half the light from M87 is emitted. Along with the light
profile for the
minor axis of M87, an ellipticity of 2.335 was calculated.
References:
Elmegreen,
D.M. 1998, Galaxies and Galactic Structure (New Jersey: Prentice Hall)
Nemiroff, R. and
Bonnell, J., Elliptical
Galaxy M87 1995, Astronomy Picture of the Day
Owen,
F., Biretta, J., Eilek, J., M87
as a Radio Galaxy, Jan. 1999
Students
for the Exploration and Development of Space, M87,
Jan. 2000
Students for the
Exploration and Development of Space, X-Ray
image of M87, Sept 2001.
Observation
Details |
Coordinates |
RA (J2000)
12:30:49.43 |
Dec
(J2000) +12:23:27.7 |
This
is in the constellation Coma. North is up and East is to the left.
|
| Scale |
The image is 21.5 by 14.5 arcmin, which
is 375,200 by 253,000 light years at the distance of M87. |
| Filter |
Clear |
B |
V |
R |
| Exposure time
per filter |
25
x 60s |
16
x 300s |
8
x 300s |
8
x 300s |
| Dates of observation |
2005
Feb.8 |
2005
Mar.8 |
2005
Mar. 10 |
2005
Apr.6 |
| Processing
details: |
Images
were dark subtracted and flat-fielded to remove noise. The images
from each filter were then combined to produce a high sensitivity
image in each filter. All 4 images were combined to produce a color
image, and a non-linear (gamma) transform was applied to bring out
faint detail in the filaments without saturating the bright, middle
region. |
|
|
