Three galaxies are playing a game of gravitational
tug-of-war that may result in the eventual demise of one of them. A new NASA
Hubble Space Telescope image shows the push and pull in action.
Located about 100 million light-years away in the constellation
Piscis Austrinus (the Southern Fish), the galaxy interaction may ultimately
lead to the three reforming into two larger star
cities.
The three galaxies — NGC 7173 (middle left), NGC 7174
(middle right), and NGC 7176 (lower right) — are part of Hickson Compact Group
90, named after astronomer Paul Hickson, who first cataloged these small
clusters of galaxies in the 1980s. NGC 7173 and NGC 7176 appear to be smooth,
normal elliptical galaxies without much gas
and dust.
In stark contrast, NGC 7174 is a mangled spiral galaxy
that appears as though it is being ripped apart by its close neighbors. The
galaxies are experiencing a strong gravitational interaction, and as a result,
a significant number of stars have been ripped away
from their home galaxies. These stars are now spread out, forming a tenuous
luminous component in the galaxy group.
Ultimately, astronomers believe that NGC 7174 will be
shredded and only the two "normal" elliptical galaxies (NGC 7173 and
NGC 7176) will remain.
Hubble imaged these galaxies with the Advanced Camera for
Surveys in May 2006.
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