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Астронет: Астрономическая картинка дня Наблюдение темной материи Галактики http://variable-stars.ru/db/msg/1161803/eng |
Credit & Copyright: OGLE Event #1, B. Paczynski, A. Udalski and the
OGLE Collaboration
Explanation:
What is our
Galaxy made of?
Stellar motions indicate there is much more
mass than just
stars and
gas.
Photographs like the two shown above may be yielding a clue about the
dark matter, however.
Pictured is the first recorded instance of a dim star in our Galaxy
moving in front of a bright background star, shown by the arrow, deflecting
light around it, and causing the background star to appear much brighter
(right frame). Were our Galaxy made predominantly of MAssive Compact Halo
Objects (MACHOs), many similar such gravitational lensing events would be
expected when photographing the
Large Magellanic Clouds (LMC) - hence
indicating the presence of MACHO lenses in our Galaxy. A
research team led
by Charles Alcock this month
claimed enough LMC gravitational lensing events to
indicate at least half of the dark matter in our Galaxy is composed of
MACHOs. This spectacular claim may well be correct - but awaits crucial
testing with future observations and modeling.
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.