Scientists last week released one of the best gamma ray light maps of our universe, revealing new sources of this high-energy emission. The sky map was constructed using more than six years’ worth of data collected by NASA’s Fermi Gamma-Ray Space Telescope.
Launched in 2008, the Fermi Large Area Telescope (LAT) measures gamma-ray light, which is the most energetic form of electromagnetic radiation. It is a billion times more energetic than the visible light that is detected by our eyes. This type of radiation is produced by interstellar phenomena such as black holes, merging neutron stars and other extreme sources such as pulsars and blazars. Scientists are using the information collected by the Fermi telescope to study subatomic particles, explore black holes, and gain other valuable information about the formation of the universe.
The latest sky map is the result of a re-analysis of existing Fermi data including every gamma-ray and particle detected by the telescope since its launch in 2008. The new Pass 8 analysis allowed the scientists to extract even more information from the telescope’s high-energy observations and provided astrophysicists with the most detailed gamma-ray census of the sky to date.
The team cataloged 360 sources, most of which were blazars. Blazars have a bright nucleus that contain a supermassive black hole and, unlike quasars, are oriented toward the Earth. The newly analyzed data has identified 48 new gamma-ray sources previously undetected at any other wavelength and twelve high-energy sources capable of producing gamma rays with energies that are a trillion times that of visible light. As noted by scientist Alberto Domínguez from Madrid’s Complutense University, “The highest-energy sources, all located in our galaxy, are mostly remnants of supernova explosions and pulsar wind nebulae, places where rapidly rotating neutron stars accelerate particles to near the speed of light.”
Fermi scientist Marco Ajello of Clemson University in South Carolina presented the team’s findings last week at the 227th meeting of the American Astronomical Society in Kissimmee, Florida. A paper describing the survey will be published in The Astrophysical Journal Supplement.
