Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.astronet.ru/db/xware/msg/apod/2000-03-24
Дата изменения: Wed Nov 8 22:40:26 2006
Дата индексирования: Sat Dec 29 06:53:51 2007
Кодировка:
A Mystery in Gamma Rays
Astronomy Picture of the Day
    


A Mystery in Gamma Rays
<< Yesterday 24.03.2000 Tomorrow >>
A Mystery in Gamma Rays
Credit: N. Gehrels, D. Macomb, D. Bertsch, D. Thompson, R. Hartman (GSFC), EGRET, NASA
Explanation: Gamma rays are the most energetic form of light, packing a million or more times the energy of visible light photons. What if you could see gamma rays? If you could, the familiar skyscape of steady stars would be replaced by some of the most bizarre objects known to modern astrophysics -- and some which are unknown. When the EGRET instrument on the orbiting Compton Gamma-ray Observatory surveyed the sky in the 1990s, it cataloged 271 celestial sources of high-energy gamma-rays. These sources are very different from the powerful gamma-ray bursters that flash and fade rapidly from view, and researchers identified some with exotic black holes, neutron stars, and distant flaring galaxies. But 170 of the cataloged sources, shown in the above all-sky map, remain unidentified. Many sources in this gamma-ray mystery map likely belong to the already known classes of gamma-ray emitters and are simply obscured or too faint to be otherwise positively identified. However, astronomers recently called attention to the ribbon of sources winding through the plane of the galaxy, projected here along the middle of the map, which may represent a large unknown class of galactic gamma-ray emitters. In any event, the unidentified sources could remain a mystery until the planned launch of the more sensitive Gamma-ray Large Area Space Telescope in 2005.

January
February
March
April
May
June
July
August
September
October
November
December
 < March 2000  >
Mo Tu We Th Fr Sa Su


12345
6789101112
13141516171819
20212223242526
2728293031

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.

Based on Astronomy Picture Of the Day

Publications with keywords: gamma ray
Publications with words: gamma ray
See also:
All publications on this topic >>