The Virgo Cluster: Hot Plasma and Dark Matter
Credit & Copyright: R. Mushotzky and S. Snowden
LHEA/
GSFC,
ROSAT
Explanation:
This ROSAT image of the
Virgo cluster of galaxies reveals a
hot X-ray emitting plasma or gas with a
temperature of 10-100 million degrees pervading
the cluster. False colors have been used to represent
the intensity of X-ray emission.
The large area of X-ray emission, just below and left of center,
is about 1 million light-years across.
The
giant elliptical galaxy M87,
the biggest member
of the cluster, is centered in that area while
other cluster members
are scattered around it.
By adding up the amount of
X-ray emitting gas astronomers
have found that its total mass is
up to 5 times the total mass of the cluster galaxies themselves -
yet all this
matter still does not produce nearly enough gravity to keep
the cluster from flying apart! Where is the unseen mass?
Because galaxy clusters are the
largest structures in the Universe, this
mysterious Dark Matter must dominate the cosmos
but its nature is still an
open question.
Information:
The
Scale of the Universe Debate in April 1996
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
