Hickson 91 in Piscis Austrinus
Explanation:
Scanning the skies for galaxies, Canadian astronomer
Paul Hickson and colleagues identified some 100 compact
groups
of galaxies, now appropriately called
Hickson Compact Groups (HCGs).
This sharp telescopic image
captures one such
galaxy group,
HCG 91, in beautiful detail.
The group's three colorful spiral galaxies at the
center of the field of view are locked in
a gravitational tug of war,
their interactions producing faint but visible
tidal tails over 100,000 light-years long.
Their close encounters trigger
furious star formation.
On a cosmic timescale the
result
will be a merger into a large single galaxy,
a process now understood to be a normal part of the
evolution of galaxies, including
our own Milky Way.
HCG 91 lies about 320 million light-years away in
the constellation
Piscis
Austrinus.
But the impressively
deep
image also catches evidence of fainter tidal
tails and galaxy interactions close to 2 billion light-years distant.
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.
