SIMBAD references

2000ApJ...529L..65D - Astrophys. J., 529, L65-L68 (2000/February-1)

The discovery of a microarcsecond quasar: J1819+3845.


Abstract (from CDS):

We report on the discovery of a source that exhibits over 300% amplitude changes in radio flux density on the period of hours. This source, J1819+3845, is the most extremely variable extragalactic source known in the radio sky. We believe these properties are due to interstellar scintillation and show that the source must emit at least 55% of its flux density within a radius of fewer than 16 µas at 5 GHz. The apparent brightness temperature is greater than 5x1012 K, and the source may be explained by a relativistically moving source with a Doppler factor of ∼15. The scattering occurs predominantly in material only a few tens of parsecs from the Earth, which explains its unusually rapid variability. If the source PKS 0405-385 is similarly affected by local scattering material, Doppler factors of ∼1000 are not required to explain this source. The discovery of a second source whose properties are well modeled by interstellar scintillation strengthens the argument for this as the cause for much of the variation seen in intraday variables.

Abstract Copyright:

Journal keyword(s): ISM: General - Galaxies: Quasars: Individual: Alphanumeric: J1819+3845 - Radiation Mechanisms: Nonthermal

Simbad objects: 6

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