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On the Location of the gamma-Ray Outburst Emission in the BL Lacertae Object AO 0235 + 164 Through Observations Across the Electromagnetic SpectrumWe present observations of a major outburst at centimeter, millimeter, optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization, as well as changes in Very Long Baseline Array images at A = 7 mm with approx.0.15 milliarcsec resolution. The association of the events at different wavebands is confirmed at high statistical significance by probability arguments and Monte Carlo simulations. A series of sharp peaks in optical linear polarization, as well as a pronounced maximum in the 7 mm polarization of a superluminal jet knot, indicate rapid fluctuations in the degree of ordering of the magnetic field. These results lead us to conclude that the outburst occurred in the jet both in the quasi-stationary "core" and in the superluminal knot, both parsecs downstream of the supermassive black hole. We interpret the outburst as a consequence of the propagation of a disturbance, elongated along the line of sight by light-travel time delays, that passes through a standing recollimation shock in the core and propagates down the jet to create the superluminal knot. The multi-wavelength light curves vary together on long timescales (months/ years), but the correspondence is poorer on shorter timescales. This, as well as the variability of the polarization and the dual location of the outburst, agrees with the expectations of a multi-zone emission model in which turbulence plays a major role in modulating the synchrotron and inverse Compton fluxes.
Document ID
20110023638
Document Type
Reprint (Version printed in journal)
Authors
Agudo, Ivan (Instituto de Astrofisica de Andalucia Granada, Spain)
Marscher, Alan P. (Boston Univ. Boston, MA, United States)
Jorstad, Svetlana G. (Saint Petersburg Univ. Saint Petersburg, Russian Federation)
Larionov, Valeri M. (Saint Petersburg Univ. Saint Petersburg, Russian Federation)
Gomez, Jose L. (Instituto de Astrofisica de Andalucia Granada, Spain)
Laehteenmaeki, Anne (Metsahovi Radio Observatory (Aalto Univ.) Finland)
Smith, Paul S. (Arizona Univ. Tucson, AZ, United States)
Nilsson, Kari (Turku Univ. Finland)
Readhead, Anthony C. S. (California Inst. of Tech. Pasadena, CA, United States)
Aller, Margo F. (Michigan Univ. Ann Arbor, MI, United States)
Heidt, Jochien (Heidelberg Univ. Heidelberg, Germany)
Gurwell, Mark (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Thum, Clemens (Institut de Radio Astronomie Millimetrique Saint Martin d'Heres, France)
Wehrle, Ann E. (Space Science Inst. Boulder, CO, United States)
Nikolashvili, Maria G. (Abastumani Astrophysical Observatory Georgia, Russian Federation)
Aller, Hugh D. (Michigan Univ. Ann Arbor, MI, United States)
Benitez, Erika (Universidad Nacional Autonoma de Mexico Mexico City, Mexico)
Blinov, Dmitriy A. (Saint Petersburg Univ. Saint Petersburg, Russian Federation)
Hagen-Thorn, Vladimir A. (Saint Petersburg Univ. Saint Petersburg, Russian Federation)
Hiriart, David (Universidad Nacional Autonoma de Mexico Mexico City, Mexico)
Jannuzi, Buell T. (National Optical Astronomy Observatories Tucson, AZ, United States)
Joshi, Manasvita (Boston Univ. Boston, MA, United States)
Kimeridze, Givi N. (Abastumani Astrophysical Observatory Georgia, Russian Federation)
Kurtanidze, Omar M. (Abastumani Astrophysical Observatory Georgia, Russian Federation)
Kurtanidze, Sofia O. (Abastumani Astrophysical Observatory Georgia, Russian Federation)
Date Acquired
August 25, 2013
Publication Date
July 1, 2011
Publication Information
Publication: The Astrophysical Journal Letters
Volume: 735
Issue: 1
Subject Category
Astrophysics
Funding Number(s)
CONTRACT_GRANT: NNX08AV65G
CONTRACT_GRANT: NNX08AJ64G
CONTRACT_GRANT: NNX09AR11G
CONTRACT_GRANT: NNX09AU10G
CONTRACT_GRANT: NNX08AV61G
CONTRACT_GRANT: NNX08AU02G
Distribution Limits
Public
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