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Multi-Epoch VLBI observations of the extreme scintillator J1819+3845

Published online by Cambridge University Press:  24 February 2011

Giuseppe Cimò  and
Leonid Gurvits
Giuseppe Cimò
Affiliation:
Joint Institute for VLBI in Europe, Postbus 2, NL-9700TA, Dwingeloo, the Netherlands email: [email protected]
Leonid Gurvits
Affiliation:
Joint Institute for VLBI in Europe, Postbus 2, NL-9700TA, Dwingeloo, the Netherlands email: [email protected]
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Abstract

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The quasar J1819+3845 has shown extreme variability with flux density variations in the radio regime up to 600% in less than one hour. In case of intrinsic high varibility, the short time scale sets a limit on the size of the emitting region and allows to estimate its brightness temperature. This would exceed 1021 K in the case of J1819+3845. Even an high relativistic jet beamed and doppler boosted in our line of sight cannot explain such an extreme violation of the Inverse Compton limit (1012 K). The variability of this source has been proven to be due to scattering in the Interstellar medium by a number of different experiments. Such an explanation requires a closeby scattering screen (few parsecs) and it results in a brightness temperature of about 1014 K. Many observing campaigns have been carried on to map the innermost jet structures of J1819+3845. Here we present the results of a number of VLBI observations, including space VLBI, to search for the missing jet in this puzzling source.

Keywords

ScintillationVLBIjets
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 6 , Symposium S275: Jets at all Scales , September 2010 , pp. 192 - 193
Copyright
Copyright © International Astronomical Union 2011

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