Conveners
Exploring the Cosmos: AGN-3: Parallel-14
- Andrew Chen (University of the Witwatersrand)
Relativistic jets are among the most variable objects in the Universe. Their variability is observed at all energy bands, from radio wavelengths to gamma rays. Despite decades of efforts, many aspects of the physics of relativistic jets remain elusive. In particular, the location and the mechanisms responsible for the high-energy emission and the connection with the variability at different...
Within the MOJAVE VLBA program (Monitoring of Jets in AGN with VLBA Experiments) we accumulated observational data at 15 GHz for hundreds of gamma-ray bright active galactic nuclei jets since the beginning of the Fermi observations. We investigated a time delay between flux density of AGN parsec-scale radio emission at 15 GHz and 0.1-100 GeV Fermi LAT photon flux, taken from constructed light...
We present a study of the gamma-ray emission from the 9 brightest flat spectrum radio quasars (FSRQs) detected with the Fermi Large Area Telescope (LAT) during its first eight years of operation, with the aim of constraining the location of the gamma-ray emission from these objects.
Using the brightest flares, we find the shortest variability timescales for our sources, which we then use to...
The magnetic field strengths and topologies in blazar jets are not yet well understood. The low-frequency (radio through UV / X-rays) emission from blazars is likely dominated by non-thermal synchrotron emission from relativistic electrons in the jets and is therefore highly polarised, while in the optical through X-ray regime, unpolarised thermal radiation components, e.g., from the accretion...
The spectral energy distributions (SEDs) of some blazars exhibit an ultraviolet (UV) and/or soft Xray excess, which can be modelled with different radiation mechanisms. Polarization measurements of the UV/X-ray emission from blazars may provide new and unique information about the astrophysical environment of blazar jets and could thus help to distinguish between different emission scenarios....
