12:00 , Αίθουσα διαλέξεων "Β. Ξανθόπουλος" στο Εργαστήριο Αστρονομίας, ΑΠΘ.
Περίληψη:
Blazars
being the beamed population of AGN, are the most copious and variable
constant emitters of radiation in the Universe. The detailed processes
that give rise to those characteristics though, are still under intense
debate. In August 2008, Fermi/LAT discovered the distant blazar PKS
1502+106 (z=1.839) showing a rapid and strong gamma-ray outburst
followed by bright and variable flux over the next months. This activity
at high energies triggered an intensive multi-wavelength campaign
indicating that the outburst was accompanied by a significantly delayed
counterpart at radio bands. Utilizing ultra-high angular resolution VLBI
imaging at 15, 43, and 86 GHz, we attempt to shed light on the physics
of the jet flow right after this high-energy flare. Furthermore, we aim
at localizing the gamma-ray emitting region. In this talk the findings
of the mm-VLBI study using the Global Millimeter VLBI Array (GMVA) data
between 2009 and 2012, will be presented. These imply an accelerating
jet. The viewing angle towards the source differs between the inner and
outer jet, with the former at ~3 degrees and the latter at ~1 degree,
beyond the first milliarcsecond. A single component travelling within
the bent jet of PKS 1502+106 can be associated with the pronounced flare
both at high-energies and in radio bands.