Kenta Suzuki, Hiroshi Nagai, Motoki Kino, Jun Kataoka, Keiichi Asada, Akihiro Doi, Makoto Inoue, Monica Orienti, Gabriele Giovannini, Marcello Giroletti, Anne Lähteenmäki, Merja Tornikoski, Jonathan León-Tavares, Uwe Bach, Seiji Kameno, Hideyuki Kobayashi
Following the discovery of a new radio component right before the GeV
\gamma-ray detection since 2008 August by Fermi Gamma-ray Space Telescope, we
present a detailed study of the kinematics and lightcurve on the central sub-pc
scale of 3C 84 using the archival VLBA 43-GHz data covering the period between
2002 January to 2008 November. We find that the new component "C3", previously
reported by the observations with the VLBI Exploration of Radio Astrometry
(VERA), was already formed in 2003. The flux density of C3 increases moderately
until 2008, and then it becomes brighter rapidly after 2008. The radio core,
C1, also shows a similar trend. The apparent speed of C3 with reference to the
core C1 shows moderate acceleration from 0.10c to 0.47c between 2003 November
to 2008 November, but is still sub-relativistic. We further try to fit the
observed broadband spectrum by the one-zone synchrotron self-Compton (SSC)
model using the measured apparent speed of C3. The fit can reproduce the
observed \gamma-ray emission, but does not agree with the observed radio
spectral index between 22 and 43 GHz.
View original:
http://arxiv.org/abs/1112.0756
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