have been spotted throughout the sky, but researchers don't know how their jets form.
are radio-loud active galactic nuclei (AGN) that are characterized by intense and rapid variability across the electromagnetic spectrum.
The extreme brightness and variability of blazars
result from a chance orientation that brings one jet almost directly in line with Earth.
to thunderstorms, from dark matter to supernova remnants, catch the highlights of NASA Fermi's first five years in space.
The prior catalogues produced by Fermi contain literally thousands of gamma-ray emitters in the far-flung cosmos, corresponding to objects such as blazars
and active galactic nuclei - both associated with black holes snacking at the centres of galaxies - or pulsars, fast-spinning neutron stars that flash our neighbourhood like a distant lighthouse.
Personally I [JT] have seen flickering visually in several dwarf novae and blazars
but U Gem is the only object where I have seen it occur on multiple occasions.
It's already found hundreds of massive black holes known as blazars
and has imaged the coldest known stars in the universe.
The fastest ' things' i n the Universe are blobs of superheated plasma that are ejected from black holes that are in the cores of extremely active galaxies known as blazars
About two-thirds of the material is dedicated to invited talks covering black holes, blazars
, active galactic nuclei and galactic masers, variability and high brightness objects, and radio stars.
Researchers at The University of Texas at Austin have found new evidence to suggest that all radio-loud quasars may be blazars
and that the differences between them may be related to the angle from which they are viewed.
Since its 1991 launch aboard a shuttle, the Compton Observatory has detected 50 blazars
Symposium subjects ranged from the discovery of new gamma-ray sources, such as blazars
and supernova remnants, to the nature of mysterious dark matter and even observations of high-energy gamma rays emitted by thunderstorms.