Browsing by Subject "Active galactic nuclei"
Now showing items 1-10 of 15
-
Characterising the long-term variability of blazars in leptonic models
(MDPI, 2019)Most research on blazar variability focuses on individual flares to explain acceleration and radiation mechanisms and improve on current models. These short-time events (being minutes, hours, or days) might not be ... -
A comprehensive power spectral density analysis of astronomical time series. I. The Fermi-LAT gamma-ray light curves of selected blazars
(IOP Publishing, 2020)We present the results of the Fermi-Large Area Telescope 10 yr long light curve (LC) modeling of selected blazars: six flat-spectrum radio quasars (FSRQs) and five BL Lacertae (BL Lacs), examined in 7, 10, and 14 day ... -
The fourth catalog of active galactic nuclei detected by the Fermi large area telescope
(IOP, 2020)The fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) between 2008 August 4 and 2016 August 2 contains $2863$ objects located at high Galactic ... -
H.E.S.S. monitoring of PKS 2155-304 in 2015 and 2016
(MDPI, 2019)PKS 2155-304 is one of the brightest blazar located in Southern Hemisphere, monitored with H.E.S.S. since the first light of the experiment. Here we report multiwavelength monitoring observations collected during the ... -
Impact of ordered and disordered magnetic fields on multiwavelength emission of blazars
(IOP Publishing, 2020)We present a detailed analysis of the effects of magnetic field topology on the spectral energy distribution (SED) and spectral variability patterns (SVPs) of blazars. In order to study these effects, we have extended our ... -
The long-lasting activity in the flat spectrum radio quasar (FSRQ) CTA 102
(MDPI, 2019)The flat spectrum radio quasar CTA 102 ( z=1.032 ) went through a tremendous phase of variability. Since early 2016 the gamma-ray flux level has been significantly higher than in previous years. It was topped by a four ... -
Millimeter-wave monitoring of active galactic nuclei with the Africa millimetre telescope
(MDPI, 2019)Active galactic nuclei are the dominant sources of gamma rays outside our galaxy and are also candidates for the source of ultra-high energy cosmic rays. In addition to being emitters of broad-band non-thermal radiation ... -
Monte Carlo Simulations of Compton Polarization in Astrophysical Sources
(North-West University (South Africa)North-West University, 2020)The description of many high-energy astrophysical sources relies on the production of relativistic jets that are accompanied by the acceleration of particles up to very high energies, and the production of non-thermal ... -
Multi-wavelength variability signatures of relativistic shocks in blazar jets
(IOP Publishing, 2019)Mildly relativistic shocks that are embedded in colliding magnetohydrodynamic flows are prime sites for relativistic particle acceleration and the production of strongly variable, polarized multi-wavelength emission from ... -
New hard-TeV extreme blazars detected with the MAGIC telescopes
(IOP, 2020)Extreme high-frequency-peaked BL Lac objects (EHBLs) are blazars that exhibit extremely energetic synchrotron emission. They also feature nonthermal gamma-ray emission whose peak lies in the very high-energy (VHE, E > 100 ...