High Energy Physics Seminars

Particle acceleration in Active Galactic Nuclei

by Dr. Amit Shukla (IIT, Indore)

Monday, November 28, 2022 from to (Asia/Kolkata)
at AG-66
Description
Blazars are commonly understood as jets emerging from Active Galactic Nuclei viewed under small angles with the line of sight. The relativistic motion of the plasma boosts the non-thermal jet emission into a forward cone. It is commonly believed that the emission is produced by ultra-relativistic particles accelerated at shock waves travelling down the jet. The measured variability from blazars CTA 102 & Bl Lac and the characteristic peak-in-peak variability pattern from quasar 3C 279 on time scales of minutes observed by Fermi-LAT indicate a very compact emission region within the jet. The absence of gamma-ray pair attenuation shows that particle acceleration takes place at a distance of ten thousand gravitational radii from the black hole in a turbulent region at the end of the magnetic nozzle where the fluid dynamical kink instability drives plasma turbulence. I will also discuss strategies to discover rapid variabilities using upcoming Indian VHE telescopes during the moderate & quiescent states of the sources. The rapid variabilities detected during intermediate & quiescent states will provide information about where the energy of the twisted magnetic fields near the black hole is converted into the kinetic energy of the particles in the jets.