Now showing items 1-7 of 7

    • Characterising the long-term variability of blazars in leptonic models 

      Thiersen, Hannes; Zacharias, Michael; Böttcher, Markus (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 ...
    • H.E.S.S. monitoring of PKS 2155-304 in 2015 and 2016 

      Wierzcholska, Alicja; Zacharias, Michael; Jankowsky, Felix; Wagner, Stefan (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 ...
    • The long-lasting activity in the flat spectrum radio quasar (FSRQ) CTA 102 

      Zacharias, Michael; Böttcher, Markus; Jankowsky, Felix; Lenain, Jean-Philippe; Wagner, Stefan J. (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 

      Backes, Michael; Böttcher, Markus; Falcke, Heino (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 ...
    • Multi-wavelength variability signatures of relativistic shocks in blazar jets 

      Böttcher, Markus; Baring, Matthew G. (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 ...
    • Studies of active galactic nuclei with CTA 

      Reimer, A.; Böttcher, M. (Elsevier, 2013)
      In this paper, we review the prospects for studies of active galactic nuclei (AGN) using the envisioned future Cherenkov Telescope Array (CTA). This review focuses on jetted AGN, which constitute the vast majority of AGN ...
    • The VHE γ-ray view of the FSRQ PKS 1510-089 

      Zacharias, Michael; Prester, Dijana Dominis; Jankowsky, Felix; Lindfors, Elina; Meyer, Manuel; H.E.S.S. Collaboration; MAGIC Collaboration (MDPI, 2019)
      The flat spectrum radio quasar PKS 1510-089 is a monitored target in many wavelength bands due to its high variability. It was detected as a very-high-energy (VHE) γ-ray emitter with H.E.S.S. in 2009, and has since been a ...