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Arp 220:
Chandra Observes Titanic Merger
The Chandra observations of the peculiar galaxy Arp 220
gives new insight into what happens when two galaxies
the size of the Milky Way collide. The image shows a
bright central region at the waist of a glowing
hour-glass-shaped cloud of multimillion degree gas that
is rushing out of the galaxy at hundreds of thousands
of miles per hour. This "superwind" is thought to be
due to explosive activity generated by the formation of
hundreds of millions of new stars.
Further out, spanning a distance of 75,000 light
years, are giant lobes of hot gas. These could be
galactic remnants that have been flung into
intergalactic space by the early impact of the
collision. Whether the lobes will continue to expand
into space or fall back into Arp 220 is unknown.
In the central region of Arp 220, the Chandra
observations allowed astronomers to pinpoint an X-ray
source at the exact location of the nucleus of one of
the pre-merger galaxies. Another fainter X-ray source
nearby may coincide with the nucleus of the other
galaxy remnant. These sources could be due to
supermassive black holes at the centers of the merging
galaxies. In a few hundred million years the two
supermassive black holes could merge to produce a
larger, supermassive black hole in the center of the
conglomerate galaxy.
Arp 220, at a relatively nearby distance of about 250
million light years from Earth, is a prototype for
understanding what conditions were like in the early
universe when massive galaxies and supermassive black
holes may have been formed by numerous galaxy
collisions.
| Fast Facts for Arp 220:
|
| Credit |
NASA/SAO/CXC/J.McDowell |
| Scale
|
Image is 2 arcmin per side.
|
| Category |
Normal
Galaxies & Starburst Galaxies |
| Coordinates
(J2000) |
RA 15h 34m 57.1s | Dec +23º
30' 12" |
| Constellation
|
Serpens |
| Observation
Date |
June 24, 2000 |
| Observation
Time |
15.6 hours |
| Obs. ID
|
869 |
| Color Code
|
Intensity |
| Instrument
|
ACIS |
| Distance
Estimate |
250 million light years (redshift
z = 0.018) |
|
Release Date
|
April 19, 2002
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