Hot Gas and Dark Matter in Clusters of Galaxies
Clusters of galaxies are some of the largest structures in the
universe. Studying them provides important clues as to the
make-up of the universe, with regard to both how structures form and
the chemical composition of the universe.
The mass within a cluster is divided up between the stars (about 10%
of the cluster mass), a hot X-ray emitting gas (20% of the cluster),
and dark matter (the remaining 70%). Scientists now know that the
gravitational effect of the dark matter is responsible for holding
the cluster together. But the nature and detailed distribution of
the dark matter is still a mystery.
Corresponding X-ray image of the
Centaurus cluster of galaxies.
The X-ray emitting gas permeates the cluster, and provides clues about
the dark matter in the cluster. Suzaku's ability to determine the
energy of X-rays to high precision will aid in the study of the X-ray
gas. Suzaku will be able to measure the motion of the this gas.
We know that, overall, it is falling into the center of the cluster.
As it falls in, it should cool, and the atoms in the gas should
radiate with their characteristic energies.
However, observations previous to Suzaku do not show all the
emission lines that are expected. Suzaku has the sensitivity to
determine if these lines are really there.
In addition, Suzaku's observations will be able to help scientists
decide which models best describe the data: those that show the gas is
turbulent or those that
show the gas temperature distribution is smooth.
Publication Date: June 2005