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Correlated Multi–Wave Band Variability in the Blazar 3C 279 from 1996 to 2007

Ritaban ChatterjeeInstitute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215S. G. JorstadAstronomical Institute of St. Petersburg State University, Universitetskij Prospekt 28, Petrodvorets, 198504 St. Petersburg, RussiaAlan P. MarscherInstitute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215Haruki OhCurrent address: Department of Physics, University of California, Berkeley, CA 94720-7300I. M. McHardyDepartment of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UKM. F. AllerAstronomy Department, University of Michigan, 830 Dennison, 501 East University Street, Ann Arbor, MI 48109-1090Hugh D. AllerAstronomy Department, University of Michigan, 830 Dennison, 501 East University Street, Ann Arbor, MI 48109-1090T. J. BalonekDepartment of Physics and Astronomy, Colgate University, 13 Oak Drive, Hamilton, NY 13346H. R. MillerDepartment of Physics and Astronomy, Georgia State University, Atlanta, GA 30303W. T. RyleDepartment of Physics and Astronomy, Georgia State University, Atlanta, GA 30303G. TostiDepartment of Physics, University of Perugia, Via A. Pascoli, 06123 Perugia, ItalyO. M. KurtanidzeAbastumani Astrophysical Observatory, Mt. Kanobili, Abastumani, GeorgiaM. G. NikolashviliAbastumani Astrophysical Observatory, Mt. Kanobili, Abastumani, GeorgiaV. M. LarionovAstronomical Institute of St. Petersburg State University, Universitetskij Prospekt 28, Petrodvorets, 198504 St. Petersburg, RussiaV. A. Hagen‐ThornAstronomical Institute of St. Petersburg State University, Universitetskij Prospekt 28, Petrodvorets, 198504 St. Petersburg, Russia

2008en

ABI

Annotatsiya

We present the results of extensive multi-wave band monitoring of the blazar 3C 279 between 1996 and 2007 at X-ray energies (2-10 keV), optical R band, and 14.5 GHz, as well as imaging with the Very Long Baseline Array (VLBA) at 43 GHz. In all bands the power spectral density corresponds to "red noise" that can be fit by a single power law over the sampled timescales. Variations in flux at all three wave bands are significantly correlated. The time delay between high- and low-frequency bands changes substantially on timescales of years. A major multifrequency flare in 2001 coincided with a swing of the jet toward a more southerly direction, and in general the X-ray flux is modulated by changes in the position angle of the jet near the core. The flux density in the core at 43 GHz—increases in which indicate the appearance of new superluminal knots—are significantly correlated with the X-ray flux. We decompose the X-ray and optical light curves into individual flares, finding that X-ray leads optical variations (XO) in six flares, the reverse (OX) occurs in three flares, and there is essentially zero lag in four flares. Upon comparing theoretical expectations with the data, we conclude that (1) XO flares can be explained by gradual acceleration of radiating electrons to the highest energies, (2) OX flares can result from either light-travel delays of the seed photons (synchrotron self-Compton scattering) or gradients in maximum electron energy behind shock fronts, and (3) events with similar X-ray and optical radiative energy output originate well upstream of the 43 GHz core, while those in which the optical radiative output dominates occur at or downstream of the core.

Identifikatorlar

DOI: 10.1086/592598

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