 |
Астронет: Астрономическая картинка дня Вещество в скоплении Пуля http://www.variable-stars.ru/db/msg/1374497/eng |
Credit & Copyright: X-ray: NASA/CXC/CfA/
M. Markevitch et al.;
Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/ D.Clowe et al.
Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.
Explanation:
What's the matter with the Bullet Cluster?
This massive cluster of galaxies
(1E 0657-558)
creates
gravitational lens distortions
of background galaxies in a way that has been interpreted as strong evidence for
the leading theory: that
dark matter exists within.
Different recent analyses,
though, indicate that a less popular alternative -- modifying gravity-- could explain
cluster dynamics without
dark
matter, and provide a
more likely progenitor scenario as
well.
Currently, the
two scientific hypotheses are competing to explain the observations: it's
invisible matter
versus amended gravity.
The duel is dramatic as a clear
Bullet-proof example
of dark matter would shatter the simplicity of
modified gravity theories.
For the near future, the battle over the Bullet cluster is likely to continue as
new observations,
computer simulations, and analyses are completed.
The featured image is
a
Hubble/Chandra/Magellan composite with red depicting the
X-rays emitted by hot gas, and blue depicting the suggested
separated dark matter distribution.
Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/ D.Clowe et al.
Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.
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.