Chandra Release - May 8, 2003

Visual Description: Stephan's Quintet

The X-ray and optical images of the galaxy group Stephan's Quintet showcase a stunning section of space. The image consists of two parts: an X-ray image combined with optical data on the upper left and a slightly larger field of view optical image on the lower right.  The X-ray image is characterized by a deep blue hue, with small bright dots scattered throughout.  The optical image is colored in a rich yellow and maps the makeup of the group of galaxies.  The hurly-burly interactions in the compact group of galaxies known as Stephan's Quintet are shown in detail. The X-ray data is from the Chandra X-ray Observatory image and the optical is from the Digitized Sky Survey. Shock-heated gas, visible only with an X-ray telescope, appears as a bright blue cloud oriented vertically in the middle of the image and has a temperature of about 6 million degrees. The heating is produced by the rapid motion of a spiral galaxy intruder located immediately to the right of the shock wave in the center of the image (a galaxy labeled B in the wide field optical image on the lower right).  An intruder that may have passed through the center of the group at least twice is the faint galaxy labeled C in the wide field optical image. A fainter blue cloud in the X-ray and optical image may be a relic of past collisions. Four galaxies, A, B, D and E are strung out diagonally across the wide field optical image are at a distance of about 280 million light years from Earth. A large-appearing galaxy F in the lower left of the image was identified as a foreground galaxy at a distance of about 35 million light years, leaving the group originally identified as Stephan's Quintet with only a quartet of galaxies. However, if we include galaxy C, which is at the same distance as the other four galaxies, it becomes a quintet again!