Aims: Radio-to-TeV observations of the bright nearby (z = 0.034) blazar Markarian 501 (Mrk 501), performed from December 2012 to April 2018, are used to study the emission mechanisms in its relativistic jet.
Methods: We examined the multi-wavelength variability and the correlations of the light curves obtained by eight different instruments, including the First G-APD Cherenkov Telescope (FACT), observing Mrk 501 in very high-energy (VHE) gamma-rays at TeV energies. We identified individual TeV and X-ray flares and found a sub-day lag between variability in these two bands.
Results: Simultaneous TeV and X-ray variations with almost zero lag are consistent with synchrotron self-Compton (SSC) emission, where TeV photons are produced through inverse Compton scattering. The characteristic time interval of 5−25 days between TeV flares is consistent with them being driven by Lense-Thirring precession.
Astronomy and Astrophysics
- Pub Date:
- November 2021
- BL Lacertae objects: individual: Mrk 501;
- radiation mechanisms: non-thermal;
- radiative transfer;
- galaxies: active;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Astrophysics of Galaxies
- 10 pages, 11 figures, Astronomy and astrophysics pre-print. arXiv admin note: text overlap with arXiv:2101.10651