Gamma rays [
http://cossc.gsfc.n…] are the most energetic form of light, packing a million or more times the energy of visible light photons. What if you could see [
http://cossc.gsfc.n…] gamma rays? If you could, the familiar skyscape [
http://antwrp.gsfc.…] of steady stars would be replaced [
http://antwrp.gsfc.…] by some of the most bizarre objects known [
http://www.skypub.c…] to modern astrophysics [
http://ads.harvard.…] -- and some which are "unknown". When the EGRET [
http://lheawww.gsfc…instrument_descripti on.html ] instrument on the orbiting Compton Gamma-ray Observatory [
http://antwrp.gsfc.…] surveyed the sky in the 1990s, it cataloged 271 celestial sources [
http://cossc.gsfc.n…egret_src.html ] of high-energy gamma-rays. These sources are very different from the powerful gamma-ray bursters [
http://antwrp.gsfc.…] that flash and fade rapidly from view, and researchers identified some with exotic black holes [
http://antwrp.gsfc.…], neutron stars [
http://cossc.gsfc.n…egret_pulsars.html ], and distant flaring galaxies [
http://antwrp.gsfc.…]. But 170 of the cataloged sources, shown in the above all-sky [
http://antwrp.gsfc.…] map, remain unidentified. Many sources [
http://pao.gsfc.nas…] 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 [
http://pao.gsfc.nas…] 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 [
http://www-glast.so…] in 2005.
Explanation
Gamma rays [
http://cossc.gsfc.n…] are the most energetic form of light, packing a million or more times the energy of visible light photons. What if you could see [
http://cossc.gsfc.n…] gamma rays? If you could, the familiar skyscape [
http://antwrp.gsfc.…] of steady stars would be replaced [
http://antwrp.gsfc.…] by some of the most bizarre objects known [
http://www.skypub.c…] to modern astrophysics [
http://ads.harvard.…] -- and some which are "unknown". When the EGRET [
http://lheawww.gsfc…instrument_descripti on.html ] instrument on the orbiting Compton Gamma-ray Observatory [
http://antwrp.gsfc.…] surveyed the sky in the 1990s, it cataloged 271 celestial sources [
http://cossc.gsfc.n…egret_src.html ] of high-energy gamma-rays. These sources are very different from the powerful gamma-ray bursters [
http://antwrp.gsfc.…] that flash and fade rapidly from view, and researchers identified some with exotic black holes [
http://antwrp.gsfc.…], neutron stars [
http://cossc.gsfc.n…egret_pulsars.html ], and distant flaring galaxies [
http://antwrp.gsfc.…]. But 170 of the cataloged sources, shown in the above all-sky [
http://antwrp.gsfc.…] map, remain unidentified. Many sources [
http://pao.gsfc.nas…] 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 [
http://pao.gsfc.nas…] 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 [
http://www-glast.so…] in 2005.
Explanation
