Editor's Summary
24 April 2008
Blazars: model behaviour
Blazars are the most extreme active galactic nuclei, possessing oppositely directed plasma jets emanating from accreting supermassive black holes at near-light speeds. The jets have been modelled as being propelled by magnetic fields twisted by differential rotation of the black hole's accretion disk or inertial-frame-dragging ergosphere. Until now, this general picture of jet formation, and the exact location of the outbursts, had not been verified. Marscher et al. now report high-resolution radio images and optical polarization measurements of the blazar BL Lacertae. The new measurements reveal a bright feature in the jet that causes a double flare of radiation from optical frequencies to TeV 
-ray energies. This suggests that the event begins in a region with a helical magnetic field, in line with model predictions.
News and Views: Astrophysics: Exhaust inspection
What do you see if you peer into the exhaust of a jet engine larger than our Solar System? Only astronomers with the largest radio telescopes can see the full picture — and definitive observations are beginning to filter through.
David L. Meier
doi:10.1038/452945b
Letter: The inner jet of an active galactic nucleus as revealed by a radio-to-
-ray outburst
Alan P. Marscher, Svetlana G. Jorstad, Francesca D. D'Arcangelo, Paul S. Smith, G. Grant Williams, Valeri M. Larionov, Haruki Oh, Alice R. Olmstead, Margo F. Aller, Hugh D. Aller, Ian M. McHardy, Anne Lähteenmäki, Merja Tornikoski, Esko Valtaoja, Vladimir A. Hagen-Thorn, Eugenia N. Kopatskaya, Walter K. Gear, Gino Tosti, Omar Kurtanidze, Maria Nikolashvili, Lorand Sigua, H. Richard Miller & Wesley T. Ryle
doi:10.1038/nature06895
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