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| Paper: |
3C 345: A Precessing Jet? |
| Volume: |
299, High Energy Blazar Astronomy |
| Page: |
93 |
| Authors: |
Abraham, Z.; Caproni, A. |
| Abstract: |
VLBI observations of 3C 345 during the last 25 years showed a considerable number of superluminal components moving along curved paths with variable velocities. These motions were interpreted as helical paths, due probably to jet precession. In our work we show that the available
data are also consistent with ballistic motion for the jet components, with different velocities and position angles in the plane of the sky for each one of them. We interpreted these results in terms of a precessing jet
model, with constant Lorentz factor for the jet bulk motion, in which the differences is superluminal velocities are attributed to differences in the
angle between the jet, when the component was formed, and the line of sight. We determined the model parameters: precession period, Lorentz factor, aperture of the precessing cone and angle between the cone axis and the line of sight. The precession period we obtained coincides with one of the periods found in the historical optical light curve. We identified the epoch of formation of each superluminal component with the occurrence of a short lived optical flare and found a correlation between the flare flux density at optical wavelengths and the half life of the component, measured at radio frequencies. Finally we give limits to the masses of the black holes in the binary system assumed to be responsible for the jet precession. |
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