The complex variability of blazars: time-scales and periodicity analysis in S4 0954+65
Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole Earth Blazar Telescope (WEBT) Collaboration. The 2-min cadence...
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| Main Authors: | , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
6 May 2021
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| In: |
Monthly notices of the Royal Astronomical Society
Year: 2021, Volume: 504, Issue: 4, Pages: 5629-5646 |
| ISSN: | 1365-2966 |
| DOI: | 10.1093/mnras/stab1268 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1093/mnras/stab1268
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| Author Notes: | CM Raiteri, M Villata, VM Larionov, SG Jorstad, AP Marscher, ZR Weaver, JA Acosta-Pulido, I Agudo, T Andreeva, A Arkharov, R Bachev, E Benítez, M Berton, I Björklund, GA Borman, V Bozhilov, MI Carnerero, D Carosati, C Casadio, WP Chen, G Damljanovic, F D’Ammando, J Escudero, A Fuentes, M Giroletti, TS Grishina, AC Gupta, VA Hagen-Thorn, M Hart, D Hiriart, W-J Hou, D Ivanov, J-Y Kim, GN Kimeridze, C Konstantopoulou, EN Kopatskaya, OM Kurtanidze, SO Kurtanidze, A Lähteenmäki, EG Larionova, LV Larionova, N Marchili, G Markovic, M Minev, DA Morozova, I Myserlis, M Nakamura, AA Nikiforova, MG Nikolashvili, J Otero-Santos, E Ovcharov, T Pursimo, I Rahimov, S Righini, T Sakamoto, SS Savchenko, EH Semkov, D Shakhovskoy, LA Sigua, M Stojanovic, A Strigachev, C Thum, M Tornikoski, E Traianou, YV Troitskaya, IS Troitskiy, A Tsai, A Valcheva, AA Vasilyev, O Vince and E Zaharieva |
| Summary: | Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole Earth Blazar Telescope (WEBT) Collaboration. The 2-min cadence optical light curves provided by TESS during three observing sectors of nearly 1 month each allow us to study the fast variability in great detail. We identify several characteristic short-term time-scales, ranging from a few hours to a few days. However, these are not persistent, as they differ in the various TESS sectors. The long-term photometric and polarimetric optical and radio monitoring undertaken by the WEBT brings significant additional information, revealing that (i) in the optical, long-term flux changes are almost achromatic, while the short-term ones are strongly chromatic; (ii) the radio flux variations at 37 GHz follow those in the optical with a delay of about 3 weeks; (iii) the range of variation of the polarization degree and angle is much larger in the optical than in the radio band, but the mean polarization angles are similar; (iv) the optical long-term variability is characterized by a quasi-periodicity of about 1 month. We explain the source behaviour in terms of a rotating inhomogeneous helical jet, whose pitch angle can change in time. |
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| Item Description: | Gesehen am 20.08.2021 |
| Physical Description: | Online Resource |
| ISSN: | 1365-2966 |
| DOI: | 10.1093/mnras/stab1268 |