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Milliarcsecond-Scale Structure in the Gamma-Ray Loud Quasar PKS 1622-297

Kiyoaki Wajima·Hayley E. Bignall·Hideyuki Kobayashi·Hisashi Hirabayashi·Yasuhiro Murata·Philip G. Edwards·Masato Tsuboi·Kenta Fujisawa
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Abstract

We have made a high-resolution VLBI observation of the gamma-ray loud quasar PKS 1622-297 with the HALCA spacecraft and ground radio telescopes at 5 GHz in 1998 February, almost three years after the source exhibited a spectacular GeV gamma-ray flare. The source shows an elongated structure toward the west on the parsec scale. The visibility data are well modeled by three distinct components; a bright core and two weaker jet components. Comparison with previous observations confirms that the jet components have an apparent superluminal motion up to 12.1 h^{-1}c, with the inner jet components having lower superluminal speeds. We apply the inverse Compton catastrophe model and derive a Doppler factor, δ, of 2.45, which is somewhat lower than that of other gamma-ray loud active galactic nuclei (AGNs), suggesting the source was in a more quiescent phase at the epoch of our observation. As an alternative probe of the sub-parsec scale structure, we also present the results from multi-epoch ATCA total flux monitoring, which indicate the presence of persistent intraday variability consistent with refractive interstellar scintillation. We examine the gamma-ray emission mechanism in the light of these observations.

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Kiyoaki Wajima, Hayley E. Bignall, Hideyuki Kobayashi, Hisashi Hirabayashi, Yasuhiro Murata, Philip G. Edwards, Masato Tsuboi, Kenta Fujisawa. 2005-11-02. Milliarcsecond-Scale Structure in the Gamma-Ray Loud Quasar PKS 1622-297. https://doi.org/10.1093/pasj%2F58.2.223

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