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Flux States of Active Galactic Nuclei

1
Institute for Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany
2
Institute for Particle Physics and Astrophysics, ETH Zurich, 8093 Zurich, Switzerland
3
Experimental Physics 5, TU Dortmund, 44221 Dortmund, Germany
4
ISDC Data Centre for Astrophysics, University of Geneva, CH-1290 Versoix, Switzerland
*
Author to whom correspondence should be addressed.
also at: Department of Physics, RWTH Aachen University, 52074 Aachen, Germany.
Galaxies 2019, 7(2), 57; https://doi.org/10.3390/galaxies7020057
Received: 21 February 2019 / Revised: 24 April 2019 / Accepted: 30 April 2019 / Published: 21 May 2019
(This article belongs to the Special Issue Monitoring the Non-Thermal Universe)
Blazars are known to show variability on time scales from minutes to years covering a wide range of flux states. Studying the flux distribution of a source allows for various insights. The shape of the flux distribution can provide information on the nature of the underlying variability processes. The level of a possible quiescent state can be derived from the main part of the distribution that can be described by a Gaussian distribution. Dividing the flux states into quiescent and active, the duty cycle of a source can be calculated. Finally, this allows alerting the multi-wavelength and multi-messenger community in case a source is in an active state. To get consistent and conclusive results from flux distributions, unbiased long-term observations are crucial. Only like this is a complete picture of the variability and flux states, e.g., an all-time quiescent state, possible. In seven years of monitoring of bright TeV blazars, the first G-APD Cherenkov telescope (FACT) has collected a total of more than 11,700 hours of physics data with 1500 hours to 3000 hours per source for Mrk 421, Mrk 501, 1ES 1959+650, and 1ES 2344+51. View Full-Text
Keywords: active galactic nuclei; blazars; monitoring; TeV energies; FACT; flux states; flux distributions; duty cycle active galactic nuclei; blazars; monitoring; TeV energies; FACT; flux states; flux distributions; duty cycle
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Dorner, D.; Arbet-Engels, A.; Baack, D.; Balbo, M.; Biland, A.; Blank, M.; Bretz, T.; Bruegge, K.; Bulinski, M.; Buss, J.; Doerr, M.; Elsaesser, D.; Hildebrand, D.; Linhoff, L.; Mannheim, K.; Mueller, S.A.; Neise, D.; Neronov, A.; Noethe, M.; Paravac, A.; Rhode, W.; Schleicher, B.; Schulz, F.; Sedlaczek, K.; Shukla, A.; Sliusar, V.; von Willert, E.; Walter, R.; FACT Collaboration. Flux States of Active Galactic Nuclei. Galaxies 2019, 7, 57.

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