Conveners
Parallel 3: AGN I
- Hartmut Winkler (University of Johannesburg)
VERITAS (the Very Energetic Radiation Imaging Telescope Array System) is an array of four 12-meter imaging atmospheric Cherenkov telescopes located at Fred Lawrence Whipple Observatory in Arizona. VERITAS is sensitive to gamma rays with energies between 85 GeV to 30 TeV. First light for the four telescope array was in 2007, shortly before the launch of Fermi. VERITAS has a large extragalactic...
High-redshift (z > 3) gamma-ray blazars offer the possibility to study black hole growth, accretion processes and jet acceleration in the early Universe. The most luminous blazars, detectable out to high redshifts, tend to have the peaks in their non-thermal spectral energy distributions (SEDs) at relatively low frequencies, with the high-energy peak often appearing at MeV energies. In...
More than 250 galactic and extragalactic very-high energy gamma-ray sources have been detected to date with imaging atmospheric Cherenkov telescopes. At present, Active Galactic Nuclei (AGNs) make up about 35% of such sources, the majority of which are blazars, i.e. their jets are closely aligned with the line of sight to Earth. At lower energies, blazars also dominate the population of...
We present a spectral study of extreme blazars (also eHBL) which are
known to exhibit hard intrinsic X-ray/TeV spectra and extreme SED peak
energies. We study four eHBLs 1ES 0120+340, RGB J0710+591, 1ES 1101-
232, 1ES 1741+196 and one HBL 1ES 2322-409 using new X-ray data from
AstroSat, together with quasi-simultaneous Fermi-LAT and other archival
multi-frequency data. Three of the eHBLs...
In the radio through optical-UV/X-ray regime, blazars emit highly polarized (nonthermal) synchrotron emission. Emission from the dusty torus, broad line region, accretion disk and host galaxy is of thermal origin and unpolarized. In some cases, their contribution is visible in spectropolarimetry wherein the unpolarized thermal emission dilutes the synchrotron polarization. However, partially...
Blazar flares are ideally suited to study the extreme physics of relativistic outflows, with the primary method for this objective being physical modeling of the varying broad-band emission from blazar jets. Many of the numerical codes developed for this task, are based on the kinetic approach tracking the particle spectrum evolution due to various physical processes (acceleration, cooling,...
