Mildly relativistic, oblique shocks are frequently invoked as possible sites of relativistic particle acceleration and production of strongly variable, polarized multi-wavelength emission from relativistic jet sources ...

Very High Energy Gamma Rays (VHE; more than 100 GeV) from Cosmological Gamma Ray Sources such as blazars can be absorbed by the Extragalactic Background light (EBL), which leads to a high-energy cut-off in blazar spectral ...

Relativistic jets in active galactic nuclei (AGN) are among the most powerful astrophysical objects discovered to date. Indeed, jetted AGN studies have been considered a prominent science case for SKA, and were included ...

The flat spectrum radio quasar 4C +01.02 became one of the brightest active galactic nuclei detected at high redshift (z = 2.1) in gamma rays when it underwent a series of outbursts during several months in 2016. We monitored ...

The Automatic Telescope for Optical Monitoring is a 75cm optical telescope located at the H.E.S.S. site in Namibia. Since 2005, it monitors around 250 gamma-ray emitting AGN and has observed numerous blazar flares in several ...

Recent observations of distant gamma ray sources indicate that the universe may be more transparent to VHE-gamma-rays than expected. In this paper we study the reduction of the EBL gamma-gamma opacity due to the existence ...

The RoboPol instrument and the relevant program was developed in order to conduct a systematic study of the optical polarisation variability of blazars. Driven by the discovery that long smooth rotations of the optical ...

Recent high-energy missions have allowed keeping watch over blazars in flaring states, which provide deep insights into the engine powered by supermassive black holes. However, having a quasar caught in a very bright ...

Recent high-energy missions have allowed keeping watch over blazars in flaring states, which provide deep insights into the engine powered by supermassive black holes. However, having a blazar caught in a very bright ...

ThunderKAT is the image-plane transients programme for MeerKAT. The goal as outlined in 2010, and still today, is to find, identify and understand high-energy astrophysical processes via their radio emission (often in ...