The Structure and Emission Model of the Relativistic Jet in the Quasar 3C 279 Inferred from Radio to High-energy γ-Ray Observations in 2008-2010
Sakamoto, T.; Greiner, J.; Lähteenmäki, A.; Umana, G.; Chen, W. P.; Blandford, R. D.; Chiang, J.; Ciprini, S.; Fukazawa, Y.; Gehrels, N.; Madejski, G. M.; Reimer, A.; Tanaka, T.; Tosti, G.; Buehler, R.; Cavazzuti, E.; Hayashida, M.; Itoh, R.; Stawarz, Ł.; Uchiyama, Y.; Villata, M.; Sikora, M.; Rossi, A.; Raiteri, C. M.; Kino, M.; Larionov, V. M.; Arkharov, A. A.; Carosati, D.; Di Paola, A.; Kopatskaya, E. N.; Kurtanidze, O. M.; Larionova, E. G.; Larionova, L. V.; Morozova, D. A.; Nikolashvili, M. G.; Sigua, L. A.; Tornikoski, M.; Troitsky, I. S.; Böttcher, M.; Trigilio, C.; Leto, P.; Buemi, C. S.; Larsson, S.; Aller, H. D.; Aller, M. F.; Agudo, I.; Jorstad, S. G.; Marscher, A. P.; Ogle, P.; Lindfors, E.; Nilsson, K.; Sillanpää, A.; Takalo, L.; Szostek, A.; Efimova, N. V.; McHardy, I. M.; Yamanaka, M.; Uemura, M.; Heidt, J.; Berdyugin, A.; Max-Moerbeck, W.; Readhead, A.; Reinthal, R.; Tammi, J.; Gurwell, M. A.; Bach, U.; Gómez, J. L.; Wehrle, A. E.; Collmar, W.; Kawabata, K. S.; Richards, J. L.; Blinov, D. A.; Jordan, B.; Benítez, E.; Hiriart, D.; Bock, D. C. -J.; Nalewajko, K.; Forné, E.; Konstantinova, T. S.; Joshi, M.; Sato, S.; Sakimoto, K.; Sasada, M.; Kruehler, T.; Macquart, J. P.; Blumenthal, K.; Dolci, M.; Kimeridze, G.; Koptelova, E.; Lamerato, A.; Molina, S. N.; Roustazadeh, P.; Taylor, B.
United States, Japan, Poland, Germany, Sweden, Italy, Austria, Denmark, Australia, Spain, Russia, Mexico, Finland, Taiwan, Ireland, Georgia, United Kingdom
Abstract
We present time-resolved broadband observations of the quasar 3C 279 obtained from multi-wavelength campaigns conducted during the first two years of the Fermi Gamma-ray Space Telescope mission. While investigating the previously reported γ-ray/optical flare accompanied by a change in optical polarization, we found that the optical emission appears to be delayed with respect to the γ-ray emission by about 10 days. X-ray observations reveal a pair of "isolated" flares separated by ~90 days, with only weak γ-ray/optical counterparts. The spectral structure measured by Spitzer reveals a synchrotron component peaking in the mid-infrared band with a sharp break at the far-infrared band during the γ-ray flare, while the peak appears in the millimeter (mm)/submillimeter (sub-mm) band in the low state. Selected spectral energy distributions are fitted with leptonic models including Comptonization of external radiation produced in a dusty torus or the broad-line region. Adopting the interpretation of the polarization swing involving propagation of the emitting region along a curved trajectory, we can explain the evolution of the broadband spectra during the γ-ray flaring event by a shift of its location from ~1 pc to ~4 pc from the central black hole. On the other hand, if the γ-ray flare is generated instead at sub-pc distance from the central black hole, the far-infrared break can be explained by synchrotron self-absorption. We also model the low spectral state, dominated by the mm/sub-mm peaking synchrotron component, and suggest that the corresponding inverse-Compton component explains the steady X-ray emission.