Chandra reveals galaxy's loss is cluster's gain (Forwarded)

Steve Roy
Media Relations Dept.
Marshall Space Flight Center, Huntsville, AL

(256) 544-0034

Megan Watzke
Chandra X-ray Observatory Center, CFA, Cambridge, MA

(617) 496-7998

For release: 10/07/03

Photo release no.: 03-179

Chandra reveals galaxy's loss is cluster's gain
[http://www1.msfc.nasa.gov/NEWSROOM/n...os03-179.html]

A new image from NASA's Chandra X-ray Observatory reveals that one galaxy's loss
is a galaxy cluster's gain. The composite image of M86 -- X-ray in blue and
optical in yellow -- shows gas being swept out of the galaxy to form a long tail
more than two hundred thousand light years in length. Located in the Virgo
galaxy cluster, this giant, elliptical galaxy is moving at about 3 million miles
per hour through diffuse hot gas that pervades the cluster. The supersonic
motion of M86 produces a "ram pressure" that is stripping gas from the galaxy
and forming the spectacular tail.

M86 has been pulled into the Virgo galaxy cluster and accelerated to a high
speed by the enormous combined gravity of dark matter, hot gas, and hundreds of
galaxies that comprise the cluster. The infall of the galaxy into the cluster is
an example of the process by which galaxy groups and galaxy clusters form over
the course of billions of years.

The galaxy is no longer an "island universe" with an independent existence. It
has been captured and its gas is being swept away to mix with the gas of the
cluster, leaving an essentially gas-free galaxy orbiting the center of the
cluster along with hundreds of other galaxies.

M86 is an unusual galaxy in that it is one of a small number of galaxies that
are moving toward Earth, rather than receding with the general expansion of the
Universe. This expansion is carrying the Virgo cluster away from us at a speed
of about 2 million miles per hour, but M86 is falling into the Virgo cluster
from the far side of the cluster, giving it a net velocity of about one million
miles per hour toward Earth.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra
program.

Credits: X-ray: NASA/CXC/C. Jones, W. Forman, & S. Murray.