With the discovery of short-term variability in the flux of very-high-energy (VHE) gamma rays from the radio galaxy M 87 and preceding discoveries of extragalactic sources, H.E.S.S. is leading the way in understanding the processes involved in how these extraordinarily energetic photons are produced.
The radio galaxy M 87 is an excellent laboratory for studying the core of these galaxies, with their supermassive black holes that act as engines to accelerate particles to extremely high energies, giving out VHE gamma rays in the process.
This object can be studied, and compared to the more numerous, but more distant Blazars where the jet obscures our view of the central source. With the H.E.S.S. results, these indications are now confirmed with greater confidence.
The flux of VHE gamma rays from M 87 is quite faint that tells us that the size of the region producing the VHE gamma rays is just about the size of our Solar system (10 to the power of 13 m, only about 0.000001 % of the size of the whole radio galaxy M 87).
For M 87, we now know that we have a clear view of the central engine with H.E.S.S., thus leading to a better understanding of all extragalactic VHE gamma-ray sources.
Via:physorg
