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).
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.
