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Precession-induced Variability in AGN Jets and OJ 287




TekijätBritzen Silke, Zajaček Michal, Gopal-Krishna, Fendt Christian, Kun Emma, Jaron Frédéric, Sillanpää Aimo, Eckart Andreas

KustantajaIOP Publishing Ltd

Julkaisuvuosi2023

JournalAstrophysical Journal

Tietokannassa oleva lehden nimiASTROPHYSICAL JOURNAL

Lehden akronyymiASTROPHYS J

Artikkelin numero 106

Vuosikerta951

Numero2

Sivujen määrä38

ISSN0004-637X

eISSN1538-4357

DOIhttps://doi.org/10.3847/1538-4357/accbbc

Verkko-osoitehttps://doi.org/10.3847/1538-4357/accbbc

Rinnakkaistallenteen osoitehttps://research.utu.fi/converis/portal/detail/Publication/180578566


Tiivistelmä

The combined study of the flaring of active galactic nuclei (AGNs) at radio wavelengths and parsec-scale jet kinematics with Very Long Baseline Interferometry has led to the view that (i) the observed flares are associated with ejections of synchrotron blobs from the core, and (ii) most of the flaring follows a one-to-one correlation with the ejection of the component. Recent results have added to the mounting evidence showing that the quasi-regular component injections into the relativistic jet may not be the only cause of the flux variability. We propose that AGN flux variability and changes in jet morphology can both be of deterministic nature, i.e., having a geometric/kinetic origin linked to the time-variable Doppler beaming of the jet emission as its direction changes due to precession (and nutation). The physics of the underlying jet leads to shocks, instabilities, or ejections of plasmoids. The appearance (morphology, flux, etc.) of the jet can, however, be strongly affected and modulated by precession. We demonstrate this modulating power of precession for OJ 287. For the first time, we show that the spectral state of the spectral energy distribution (SED) can be directly related to the jet's precession phase. We model the SED evolution and reproduce the precession parameters. Further, we apply our precession model to 11 prominent AGNs. We show that for OJ 287 precession seems to dominate the long-term variability (≳1 yr) of the AGN flux, SED spectral state, and jet morphology, while stochastic processes affect the variability on short timescales (≲0.2 yr).


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