We present the analysis of the radio jet evolution of the radio galaxy 3C 120 during a period of prolonged gamma-ray activity detected by the Fermi satellite between December 2012 and October 2014. ...We find a clear connection between the gamma-ray and radio emission, such that every period of gamma-ray activity is accompanied by the flaring of the mm-VLBI core and subsequent ejection of a new superluminal component. However, not all ejections of components are associated with gamma-ray events detectable by Fermi. Clear gamma-ray detections are obtained only when components are moving in a direction closer to our line of sight.This suggests that the observed gamma-ray emission depends not only on the interaction of moving components with the mm-VLBI core, but also on their orientation with respect to the observer. Timing of the gamma-ray detections and ejection of superluminal components locate the gamma-ray production to within almost 0.13 pc from the mm-VLBI core, which was previously estimated to lie about 0.24 pc from the central black hole. This corresponds to about twice the estimated extension of the broad line region, limiting the external photon field and therefore suggesting synchrotron self Compton as the most probable mechanism for the production of the gamma-ray emission. Alternatively, the interaction of components with the jet sheath can provide the necessary photon field to produced the observed gamma-rays by Compton scattering.
We present a new method to measure Gamma*theta_j in flux-limited samples of active galactic nuclei (AGN) jets, where Gamma is the bulk Lorentz factor and theta_j is the jet's half-opening angle. The ...Gamma*theta_j parameter is physically important for models of jet launching, and also determines the effectiveness of jet instabilities and magnetic reconnection. We measure Gamma*theta_j by analyzing the observed distribution of apparent opening angles in very long baseline interferometry (VLBI) flux-limited samples of jets, given some prior knowledge of the active galactic nuclei (AGN) radio luminosity function. We then apply this method to the MOJAVE flux-limited sample of radio loud objects and find Gamma*theta_j = 0.1 +- 0.03, which implies that AGN jets are subject to a variety of physical processes that require causal connection.
Topics of the Colloquium: a) Interplanetary scintillation b) Interstellar
scintillation c) Modeling and physical origin of the interplanetary and the
interstellar plasma turbulence d) Scintillation ...as a tool for investigation of
radio sources e) Seeing through interplanetary and interstellar turbulent media
Ppt-presentations are available on the Web-site:
http://www.prao.ru/conf/Colloquium/main.html
This work devotes to investigations of solar corona and solar wind plasma by the method of radio probing with using of very long baseline interferometry (VLBI). We performed the theoretical ...calculation of power spectrum of interferometric response to radio source emission, passed through the turbulent medium. Data of theoretical analysis are compared with results of international VLBI experiments on investigations of solar wind plasma. The observations were realized in 1998, 1999, 2000 with participation of radio telescopes, included at Low Frequency VLBI Network (LFVN): Bear Lakes (RT-64, Russia), Puschino (RT-22, Russia), Urumqi (RT-25, China), Noto (RT-32, Italy), Shanghai (RT-25, China) and others. Preprocessing was carried out with using of S2 correlator at Penticton (Canada). Post processing of experimental data was performed at RRI (Russia) and was aimed to obtain value of solar wind velocity and index of spatial spectrum of electron density fluctuations.
Maps of the radio source 3C 120 obtained from VLBA+ observations at 8.4 GHz at five epochs in January - September 2002 are presented. The images were reconstructed using the maximum entropy method ...and the Pulkovo VLBImager software package for VLBI mapping. Apparent superluminal motions of the brightest jet knots have been estimated. The speeds of jet knots decreases with distance from the core, changing from 5.40+-0.48c $ to 2.00+-0.48c over 10 mas (where c is the speed of light) for a Hubble constant of 65 km/s/Mpc. This can be explained by interaction of the jet with the medium through which it propagates.
Topics of the Colloquium: a) Interplanetary scintillation b) Interstellar scintillation c) Modeling and physical origin of the interplanetary and the interstellar plasma turbulence d) Scintillation ...as a tool for investigation of radio sources e) Seeing through interplanetary and interstellar turbulent media Ppt-presentations are available on the Web-site: http://www.prao.ru/conf/Colloquium/main.html
The modern status of the SPHERE experiment and the method to determine the primary energy and the kind of the primary nuclear particles is presented. The SPHERE experiment is based on A.E.Chudakov's ...suggestion to use a new method for investigating the ultra high energy primary cosmic ray energy spectrum A.E. Chudakov,
Trudy conf. po cosm. lutcham, (in Russian), p.69, Yakutsk, 1972. A small device lifted above the snow surface of the Earth detects the Cherenkov light of extensive air showers reflected from the surface. The relatively simple detector SPHERE-2 (spherical mirror 1.5
m diameter and retina of 100 pixels) is presented. The next plan of the SPHERE experiment is to start measurements of the cosmic ray spectrum in the energy range
10
16
–
10
18
eV
above the snow surface of Lake Baikal.
