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. If you could see gamma rays, the familiar skyscape [
http://antwrp.gsfc.…] of steady stars would be replaced [
http://antwrp.gsfc.…] by some of the most bizarre objects known [
http://skyandtelesc…article_240_1.asp ] 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…] of high-energy gamma-rays. Researchers identified some with exotic black holes [
http://antwrp.gsfc.…], neutron stars [
http://antwrp.gsfc.…], and distant flaring galaxies [
http://antwrp.gsfc.…]. But 170 of the cataloged sources, shown in the above all-sky map, remain unidentified. Many sources [
http://pao.gsfc.nas…] in this gamma-ray mystery map likely belong to already known classes of gamma-ray emitters and are simply obscured or too faint to be otherwise positively identified. However, astronomers have 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 [
http://adsabs.harva…bibcode=2000HEAD...3 2.4007G&db_key=AST&h igh=3af6c03e8125794 ] 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 2007.
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. If you could see gamma rays, the familiar skyscape [
http://antwrp.gsfc.…] of steady stars would be replaced [
http://antwrp.gsfc.…] by some of the most bizarre objects known [
http://skyandtelesc…article_240_1.asp ] 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…] of high-energy gamma-rays. Researchers identified some with exotic black holes [
http://antwrp.gsfc.…], neutron stars [
http://antwrp.gsfc.…], and distant flaring galaxies [
http://antwrp.gsfc.…]. But 170 of the cataloged sources, shown in the above all-sky map, remain unidentified. Many sources [
http://pao.gsfc.nas…] in this gamma-ray mystery map likely belong to already known classes of gamma-ray emitters and are simply obscured or too faint to be otherwise positively identified. However, astronomers have 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 [
http://adsabs.harva…bibcode=2000HEAD...3 2.4007G&db_key=AST&h igh=3af6c03e8125794 ] 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 2007.
Explanation
