January 6, 2004: Trailing 200,000-light-year-long streamers of seething gas, a galaxy that was once like our Milky Way is being shredded as it plunges at 4.5 million miles per hour through the heart of a distant cluster of galaxies. In this unusually violent collision with ambient cluster gas, the galaxy is stripped down to its skeletal spiral arms as it is eviscerated of fresh hydrogen for making new stars.See the rest:
This galaxy has a strange shape reminiscent of the wake around a boat sailing across a lake. The analogy is apt because the galaxy is plowing through hot gas in the center of a galaxy cluster
The galaxy will be stripped of the hydrogen gas needed to make successive generations of stars. In that sense the galaxy will grow old prematurely. It will be left with aging stars, but no bright blue, new star clusters.
To analyze the galaxy astronomers made a variety of diagnostic observations from telescopes that record the galaxy's appearance in X-ray, optical, and radio light. The observations discovered bright star clusters on the galaxy's leading edge; the galaxy has a tail of gas; and the galaxy is surrounded by its own gas, which is leaking from it.
Though such "distressed" galaxies have been seen before, this one's demise is unusually swift and violent. That's because the galaxy belongs to a cluster of galaxies that slammed into another cluster about 100 million years ago.
Views of the early universe show that spiral galaxies were once much more abundant in rich clusters of galaxies. But they seem to have been vanishing over cosmic time. This result helps explain why.
Credit: NASA, W. Keel (U Alabama), F. Owen (NRAO), M. Ledlow (Gemini Obs.), and D. Wang (U Mass.)