European Association for Astronomy Education

Source: NASA Fermi

New sources emerge and old sources fade as the LAT's view extends into higher energies.
Credit: NASA/DOE/Fermi LAT Collaboration and A. Neronov et al.

After more than three years in space, NASA's Fermi Gamma-ray Space Telescope is extending its view of the high-energy sky into a largely unexplored electromagnetic range. Today, the Fermi team announced its first census of energy sources in this new realm.

Fermi's Large Area Telescope (LAT) scans the entire sky every three hours, continually deepening its portrait of the sky in gamma rays, the most energetic form of light. While the energy of visible light falls between about 2 and 3 electron volts, the LAT detects gamma rays with energies ranging from 20 million to more than 300 billion electron volts (GeV).

At higher energies, gamma rays are rare. Above 10 GeV, even Fermi's LAT detects only one gamma ray every four months. (read more)

Source: NASA SWIFT

Image credit: Gemini Observatory/AURA/NASA/ Levan, Tanvir, Cucchiara, Fox

NASA's Swift satellite has found the most distant gamma-ray burst ever detected. The blast, designated GRB 080913, arose from an exploding star 12.8 billion light-years away. (read more)

Source: Chandra X-Ray Observatory

GRB 110328A. Image credit:NASA/CXC/Warwick/A.Levan et al.

An extraordinary gamma-ray burst, known as GRB110328A, has been observed by a team of NASA telescopes (Chandra, Hubble, and Swift). The source of GRB110328A appears to be a galaxy about 3.8 billion light years from Earth. arly analysis of the data suggests the burst may have been caused by a star torn apart by a supermassive black hole in the galaxy's center.(read source)

Source: NASA Fermi

When FERMI detected a bem of a terrestrial gamma-ray flash (TGF) some
particles reflected off of a magnetic "mirror" point and returned.
Credit: NASA's Goddard Space Flight Center

Scientists using NASA's Fermi Gamma-ray Space Telescope have detected beams of antimatter produced above thunderstorms on Earth, a phenomenon never seen before.

Scientists think the antimatter particles were formed in a terrestrial gamma-ray flash (TGF), a brief burst produced inside thunderstorms and shown to be associated with lightning. It is estimated that about 500 TGFs occur daily worldwide, but most go undetected. (read more)

Source: ESO Science Release eso1049

Artist’s impression shows a dark gamma-ray burst in a star forming region.
Image credit: ESO/L.Calçada

Gamma-ray bursts are among the most energetic events in the Universe, but some appear curiously faint in visible light. The biggest study to date of these so-called dark gamma-ray bursts, using the GROND instrument on the 2.2-metre MPG/ESO telescope at La Silla in Chile, has found that these gigantic explosions don’t require exotic explanations. Their faintness is now fully explained by a combination of causes, the most important of which is the presence of dust between the Earth and the explosion. (read more)