nov 052012
Fermi Measures Cosmic 'Fog' Produced by Ancient Starlight

  Astronomers using data from NASA’s Fermi Gamma-ray Space Telescope have made the most accurate measurement of starlight in the Universe and used it to establish the total amount of light from all of the stars that have ever shone, accomplishing a primary mission goal. This plot shows the locations of 150 blazars (green dots) [continue reading]

okt 292012
Blazars Still Mysterious Cosmic Objects

  A blazar is a galaxy with an intensely bright central nucleus containing a supermassive black hole, much like a quasar. The difference is that a blazar can emit light with extremely high energy gamma rays that are sometimes over a hundred million times more energetic than the highest energy X-rays that the Chandra X-ray [continue reading]