A → cluster of galaxies at a
→ redshift of z = 0.296 undergoing a violent
→ merger process nearly in the
→ plane of the sky. Also known as 1E 0657-558.
The head-on collision between the main cluster and a subcluster ramming
with an apparent speed of about 4700 km s-1 occurred about
150 x 106 years ago. The two clusters are currently moving away from
each other while the space between them is filled with a very hot gas
(first observed in X-rays by → Chandra)
resulting from the overheating due to the collision.
The Bullet cluster has the highest X-ray luminosity and temperature of
all known clusters.
The X-ray gas of the bullet (amounting to 2 x 1013 solar masses)
collides with the X-ray gas of the main cluster (1014 solar masses)
and forms a well defined → supersonic
(Mach 3) → bow shock. A significant offset between the
distribution of X-ray emission and the mass distribution has been observed,
and diversely interpreted.
Etymology (EN): The name Bullet refers to the smaller subcluster, that has created the
bow shock; → cluster.
