A COLLISION IN THE HEART OF A GALAXY
The Hubble Space Telescope's Near Infrared Camera and
Multi-Object Spectrometer (NICMOS) has uncovered a collision
between two spiral galaxies in the heart of the peculiar
galaxy called Arp 220. The collision has provided the spark
for a burst of star formation.
The NICMOS image captures bright knots of stars forming in
the heart of Arp 220. The bright, crescent moon-shaped object
is a remnant core of one of the colliding galaxies. The core
is a cluster of 1 billion stars. The core's half-moon shape
suggests that its bottom half is obscured by a disk of dust
about 300 light-years across. This disk is embedded in the
core and may be swirling around a black hole. The core of
the other colliding galaxy is the bright round object to the
left of the crescent moon-shaped object. Both cores are about
1,200 light-years apart and are orbiting each other.
Arp 220, located 250 million light-years away in the
constellation Serpens, is the 220th object in Halton
Arp's Atlas of Peculiar Galaxies.
The image was taken with three filters. The colors have been
adjusted so that, in this infrared image, blue
corresponds to shorter wavelengths, red to longer wavelengths.
The image was taken April 5, 1997.
Credits: Rodger Thompson, Marcia Rieke, Glenn Schneider
(University of Arizona) and Nick Scoville (California
Institute of Technology), and NASA
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