Relentless multi-wavelength variability of Markarian 421 and Markarian 501

Discussion timeslot (ZOOM-Meeting): 15. July 2021 - 12:00
ZOOM-Meeting URL: https://desy.zoom.us/j/98542982538
ZOOM-Meeting ID: 98542982538
ZOOM-Meeting Passcode: ICRC2021
Corresponding Session: https://icrc2021-venue.desy.de/channel/49-Studying-the-variable-emission-from-AGN-in-a-multi-wavelength-context-GAD-GAI-MM/119
Live-Stream URL: https://icrc2021-venue.desy.de/livestream/Discussion-04/5

Abstract:
'The high-synchrotron-peaked blazars Markarian 421 and Markarian 501 are close bright and well-studied active galactic nuclei, which feature persistent GeV and TeV emission. FACT and Fermi-LAT have been monitoring these two sources providing the densest long-term dataset of unbiased gamma ray observations. Light curves in the TeV and GeV energy bands, spanning over a five-year period, were used to study the multi-wavelength emission. To characterize the variability and derive constraints on the emission mechanism model parameters, the dataset was augmented with contemporaneous multi-wavelength observations from radio to the X-rays. The blazars were found in various activity states, particularly a quiescent state of Markarian 501 after August, 2016. We correlate the light curves from radio to gamma rays, identify individual flares and look for inter-band connections, which are expected from the shock propagations within the jet. The fractional variability for both blazars shows a two-bump structure with the highest variability in the X-ray and TeV bands. The lag between X-ray and TeV light curves in Markarian 421 was found to be close to zero, supporting the SSC emission scenario. The timing between both TeV and X-ray flares in Markarian 421 is consistent with periods expected in the case of Lense–Thirring precession of the accretion disc. The variability of Markarian 501 on the long-term scale is also consistent with SSC, with a sub-day lag between X-ray and TeV variability.'

Authors: Sliusar Vitalii
Co-Authors: Axel Arbet-Engels | Dominik Baack | Matteo Balbo | Noah Biederbeck | Adrian Biland | Thomas Bretz | Jens Buss | Daniela Dorner | Laura Eisenberger | Dominik Elsaesser | Dorothee Hildebrand | Roman Iotov | Karl Mannheim | Dominik Neise | Maximilian Noethe | Aleksander Paravac | Wolfgang Rhode | Bernd Schleicher | Roland Walter
Collaboration: FACT

Indico-ID: 433
Proceeding URL: https://pos.sissa.it/395/808