Multi-Frequency Monitoring of the Flat Spectrum Radio Quasar PKS 1222+216 in 2008–2015
AbstractWe analyze the broadband activity of the flat spectrum radio quasar PKS 1222+216 from 2008 to 2015 using multi-frequency monitoring which involves γ-ray data from the Fermi Large Area Telescope, total intensity and linear polarization observations from different optical telescopes in R band, and imaging of the inner jet structure with the Very Long Baseline Array (VLBA) at 43 GHz. During the observations, the source showed several dramatic flares at γ rays and optical bands, with the rising branch of a γ-ray flare accompanied by a rapid rotation of the polarization position angle (EVPA), a fast increase of the degree of polarization in the optical band, brightening of the VLBI core, and appearance of a new superluminal component in the parsec-scale jet. The rapid variability of the optical linear polarization may be explained by a strong turbulence in the jet plasma. We find a correlation between the γ rays, optical R band, and 43 GHz variability on a long-term scale (months and years), and a good general alignment between EVPAs in R band and at 43 GHz, while the correlation between short-term variations (days and weeks) is weaker. Synchronous activity across the bands supports the idea that the emission regions responsible for the γ-ray and optical flares are co-spatial and located in the vicinity of the mm-wave core of the parsec-scale jet. However, these connections do not completely explain the challenging behaviour of PKS 1222+216, since there are some γ-ray flares which are not accompanied by jet events, and vice versa. We need a continuation of multi-frequency monitoring along with high resolution imaging of the parsec-scale jet to understand in detail the origin of high energy emission in blazars. View Full-Text
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Troitskiy, I.; Morozova, D.; Jorstad, S.; Larionov, V.; Marscher, A.; Agudo, I.; Blinov, D.; Smith, P.; Troitskaya, Y. Multi-Frequency Monitoring of the Flat Spectrum Radio Quasar PKS 1222+216 in 2008–2015. Galaxies 2016, 4, 72.
Troitskiy I, Morozova D, Jorstad S, Larionov V, Marscher A, Agudo I, Blinov D, Smith P, Troitskaya Y. Multi-Frequency Monitoring of the Flat Spectrum Radio Quasar PKS 1222+216 in 2008–2015. Galaxies. 2016; 4(4):72.Chicago/Turabian Style
Troitskiy, Ivan; Morozova, Daria; Jorstad, Svetlana; Larionov, Valery; Marscher, Alan; Agudo, Ivan; Blinov, Dmitry; Smith, Paul; Troitskaya, Yuliya. 2016. "Multi-Frequency Monitoring of the Flat Spectrum Radio Quasar PKS 1222+216 in 2008–2015." Galaxies 4, no. 4: 72.
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