WISE, Fermi missions reveal a surprising blazar connection August 24, 2016 by Francis Reddy Please Register or Log in to view the hidden image! An analysis of blazar properties observed by the Wide-field Infrared Survey Explorer (WISE) and Fermi's Large Area Telescope (LAT) reveal a correlation in emissions from the mid-infrared to gamma rays, an energy range spanning a factor of 10 billion. When plotted by gamma-ray and mid-infrared colors, confirmed Fermi blazars (gold dots) form a unique band not shared by other sources beyond our galaxy. A blue line marks the best fit of these values. The relationship allows astronomers to identify potential new gamma-ray blazars by studying WISE infrared data. Credit: NASA's Goddard Space Flight Center/Francesco Massaro, University of Turin Astronomers studying distant galaxies powered by monster black holes have uncovered an unexpected link between two very different wavelengths of the light they emit, the mid-infrared and gamma rays. The discovery, which was accomplished by comparing data from NASA's Wide-field Infrared Survey Explorer (WISE) and Fermi Gamma-ray Space Telescope, has enabled the researchers to uncover dozens of new blazar candidates. extract: Blazars constitute more than half of the discrete gamma-ray sources seen by Fermi's Large Area Telescope (LAT). At the heart of a blazar lies a supersized black hole with millions of times the sun's mass surrounded by a disk of hot gas and dust. As material in the disk falls toward the black hole, some of it forms dual jets that blast subatomic particles straight out of the disk in opposite directions at nearly the speed of light. A blazar appears bright to Fermi for two reasons. Its jets produce many gamma rays, the highest-energy form of light, and we happen to be viewing the galaxy face on, which means one of its jets is pointing in our direction. Read more at: http://phys.org/news/2016-08-wise-fermi-missions-reveal-blazar.html#jCp
http://iopscience.iop.org/article/1...28530723326282DCAC2.c4.iopscience.cld.iop.org THE INFRARED–GAMMA-RAY CONNECTION: A WISE VIEW OF THE EXTRAGALACTIC GAMMA-RAY SKY Abstract Using data from the Wide-field Infrared Survey Explorer (WISE) all-sky survey, we discovered that the nonthermal infrared (IR) emission of blazars, the largest known population of extragalactic γ-ray sources, has peculiar spectral properties. In this work, we confirm and strengthen our previous analyses using the latest available releases of both theWISE and the Fermi source catalogs. We also show that there is a tight correlation between the mid-IR colors and the γ-ray spectral index of Fermi blazars. We name this correlation the infrared–γ-ray connection. We discuss how this connection links both the emitted powers and the spectral shapes of particles accelerated in jets arising from blazars over 10 decades in energy. Based on this evidence, we argue that the infrared–γ-ray connection is stronger than the well-known radio–γ-ray connection.
