A1 Refereed original research article in a scientific journal
A connection between γ-ray and parsec-scale radio flares in the blazar 3C 273
Authors: Lisakov MM, Kovalev YY, Savolainen T, Hovatta T, Kutkin AM
Publisher: OXFORD UNIV PRESS
Publication year: 2017
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Journal acronym: MON NOT R ASTRON SOC
Volume: 468
Issue: 4
First page : 4478
Last page: 4493
Number of pages: 16
ISSN: 0035-8711
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/stx710
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/23345532
We present a comprehensive 5-43 GHz VLBA study of the blazar 3C 273 initiated after an onset of a strong gamma-ray flare in this source. We have analysed the kinematics of newborn components, light curves and position of the apparent core to pinpoint the location of the gamma-ray emission. Estimated location of the gamma-ray emission zone is close to the jet apex, 2-7 pc upstream from the observed 7 mm core. This is supported by ejection of a new component. The apparent core position was found to be inversely proportional to frequency. The brightness temperature in the 7 mm core reached values up to at least 1013 K during the flare. This supports the dominance of particle energy density over that of magnetic field in the 7 mm core. Particle density increased during the radio flare at the apparent jet base, affecting synchrotron opacity. This manifested itself as an apparent core shuttle along the jet during the 7 mm flare. It is also shown that a region where optical depth decreases from tau similar to 1 to tau << 1 spans over several parsecs along the jet. The jet bulk flow speed estimated at the level of 12c on the basis of time lags between 7 mm light curves of stationary jet features is 1.5 times higher than that derived from very long baseline interferometry apparent kinematics analysis.
Keywords:
gamma-rays: galaxies, quasars: individual: 3C 273, radio continuum: galaxies, techniques: interferometric
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