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Астронет: Астрономическая картинка дня NGC 3314: когда галактики перекрываются http://variable-stars.ru/db/msg/1785210/eng |
Credit & Copyright: NASA,
ESA, Hubble;
Processing & Copyright:
William Ostling
(The Astronomy Enthusiast)
Explanation:
Why doesn't the nearby galaxy create a
gravitational lensing effect on the background galaxy?
It does, but since both
galaxies
are so nearby, the angular shift is much smaller than the angular
sizes
of the galaxies themselves.
The featured
Hubble image of
NGC 3314
shows two large spiral galaxies which happen to
line up exactly.
The foreground spiral
NGC 3314a appears nearly face-on with its
pinwheel shape defined by young bright star clusters.
Against the glow of the background galaxy NGC 3314b, though, dark swirling lanes
of
interstellar dust can also be seen tracing the nearer spiral's structure.
Both galaxies appear on the edge of the
Hydra Cluster of Galaxies,
a cluster that is about 200 million light years away.
Gravitational lens distortions
are much easier to see when the
lensing galaxy is smaller and further away.
Then, the background galaxy may even be distorted into a
ring around the nearer.
Fast gravitational lens flashes due to stars in the foreground galaxy
momentarily magnifying the light from stars in the background galaxy might one
day be visible in future observing campaigns with high-resolution telescopes.
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.