Hubble brings galaxies out of coma
BY DR EMILY BALDWIN
ASTRONOMY NOW
Posted: June 11, 2008

NASA’s Hubble Space Telescope has captured the magnificent starry population of the Coma Cluster galaxies, one of the densest known galaxy stockpiles in the Universe.

The Coma Cluster galaxies. A particularly bright spiral galaxy stands out in the upper left of the image. Image: NASA, ESA, Hubble Heritage Team (STScI/AURA).

The Coma Cluster is over 300 million light years away near the Milky Way’s north pole, in an area unobscured by dust and gas from the plane of the Milky Way. It contains thousands of galaxies in a spherical shape more than 20 million light years in diameter, and Hubble homed in on a section of the cluster that is roughly one-third the way out from its centre.

Most of the galaxies that occupy the central portion of the Coma Cluster are pale gold-brown ellipticals, containing populations of old stars. Further out are spiral galaxies giving birth to new stars, accessorized by spiral arms and dust lanes. There are also a sprinkling of transitional galaxies which are made up of older stars but also show hints of a structure such as a bar or ring.

In the image above, one particularly bright, blue spiral galaxy stands out (upper left). A series of dusty spiral arms appears reddish brown against the whiter disk of the galaxy, and suggests that this galaxy has been disturbed at some point in the past. The other prominent galaxies in the image are ellipticals; the background galaxies lie far beyond the Coma Cluster sphere.

The data of the Coma Cluster were taken as part of a survey of a nearby rich galaxy cluster. Collectively they will provide a key database for studies of galaxy formation and evolution. This survey will also help to compare galaxies in different environments, both crowded and isolated, as well as to compare relatively nearby galaxies to more distant ones.