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Астронет: Астрономическая картинка дня Секретная спираль IC 3328 http://variable-stars.ru/db/msg/1166623/eng |
Credit & Copyright: H. Jerjen,
A. Kalnajs
(Australian National Univ.),
B. Binggeli (A.I.
University of Basel),
ESO
Explanation:
IC3328 is an otherwise unremarkable dwarf
elliptical galaxy
about 50 million light-years away in the
Virgo cluster.
But hidden within IC3328 is a subtle,
beautifully symmetric spiral structure!
A team
of astronomers recently made
this totally surprising discovery using
detailed digital images from the European Southern
Observatory's 8.2 meter Antu telescope.
They numerically modeled the smooth distribution of light for
this galaxy (left) to enable more accurate measurements
of its distance.
When the smooth distribution was
subtracted from the digital image, the startling spiral
structure became apparent (right).
Typical of large, rotating,
disk galaxies with density waves,
spiral structure is unprecedented
in the blob-shaped aggregates of stars normally
classified
as elliptical galaxies.
What created the "secret"
spiral
in IC3328?
Some possibilities under consideration include tidal interactions with
nearby galaxies and amplified internal stellar motions.
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.