Astronomy Picture of the Day
    


NGC 922: Collisional Ring Galaxy
<< Yesterday 17.12.2012 Tomorrow >>
NGC 922: Collisional Ring Galaxy
Credit & Copyright: NASA, ESA; Acknowledgement: Nick Rose
Explanation: Why does this galaxy have so many big black holes? No one is sure. What is sure is that NGC 922 is a ring galaxy created by the collision of a large and small galaxy about 300 million years ago. Like a rock thrown into a pond, the ancient collision sent ripples of high density gas out from the impact point near the center that partly condensed into stars. Pictured above is NGC 922 with its beautifully complex ring along the left side, as imaged recently by the Hubble Space Telescope. Observations of NGC 922 with the Chandra X-ray Observatory, however, show several glowing X-ray knots that are likely large black holes. The high number of massive black holes was somewhat surprising as the gas composition in NGC 922 -- rich in heavy elements -- should have discouraged almost anything so massive from forming. Research is sure to continue. NGC 922 spans about 75,000 light years, lies about 150 million light years away, and can be seen with a small telescope toward the constellation of the furnace (Fornax).

January
February
March
April
May
June
July
August
September
October
November
December
 < December 2012  >
Mo Tu We Th Fr Sa Su





12
3456789
10111213141516
17181920212223
24252627282930
31





Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

Based on Astronomy Picture Of the Day

Publications with keywords: ring galaxy - spiral galaxy - colliding galaxies
Publications with words: ring galaxy - spiral galaxy - colliding galaxies
See also:
All publications on this topic >>