Elizaveta Rastorgueva-Foi

The connection between the parsec-scale radio jet and γ-ray flares in the blazar 1156+295

The blazar 1156+295 was active atγ-ray energies, exhibiting three prominent flares during the year 2010. Here, we present results using the combination of broadband (X-ray through mm single dish) monitoring data and radio band imaging data at 43 GHz on the connection ofγ-ray events to the ejections of superluminal components and other changes in the jet of 1156+295. The kinematics of the jet over the interval 2007.0‐2012.5 using 43 GHz Very Long Baseline Array observations, reveal the presence of four moving and one stationary component in the inner region of the blazar jet. The propagation of the third a nd fourth components in the jet corresponds closely in time to the active phase of the source in γ rays. We briefly discuss the implications of the structural changes in the jet for the mec hanism of γ-ray production during bright flares. To localise the γ-ray emission site in the blazar, we performed the correlati on analysis between the 43 GHz radio core and the γ-ray light curve. The time lag obtained from the correlation constrains the γ-ray emitting region in the parsec-scale jet.

Results from the regional AUSTRAL VLBI sessions for Southern Hemisphere reference frames

The AUSTRAL observing program is an initiative led by the Australian AuScope VLBI antennas in collaboration with radio telescopes in Warkworth, New Zealand, and Hartebeesthoek, South Africa. In 2014 the number of AUSTRAL sessions increased tremendously. Comparing recent results to the standard products achieved in global VLBI sessions regularly undertaken by the International VLBI Service for Geodesy and Astrometry (IVS), better accuracies in terms of baseline length repeatabilities are found for these regional AUSTRAL sessions. The network of (almost) identical small and fast telescopes as well as the technical equipment at all stations allows for new observing modes and improved operations, as such serving as a testbed for the future VLBI Global Observing System (VGOS). Special AUST-Astro sessions are used for dedicated astrometry of sparsely observed radio sources in the southern sky, as well as for detecting new radio sources for geodesy. In 2015, the AUSTRAL program will be further increased and final steps are now being undertaken for full VGOS compatibility of the three AuScope VLBI antennas. We present the latest results of the AUSTRAL sessions and give an overview of the multiple areas of research they support.

Proper motions of embedded protostellar jets in Serpens

Context. To investigate the dynamical properties of protostellar jets. Aims. Determine the proper motion of protostellar jets around Class 0 and Class I sources in an active star forming region in Serpens. Methods. Multi-epoch deep images in the 2.122

Connection between parsec-scale radio jet and gamma-ray flares in the blazar 1156+295

\mu

VLBI observations of blazar 0716+714 during the outburst in spring 2004

m line of molecular hydrogen, v=1-0 S(1), obtained with the near-infrared instrument NOTCam over a time-scale of 10 years, are used to determine proper motion of knots and jets. K-band spectroscopy of the brighter knots is used to supply radial velocities, estimate extinction, excitation temperature, and H

The Outburst of the Blazar S4 0954+658 in 2011 March-April

_2

A Multi-wavelength Polarimetric Study of the Blazar CTA 102 during a Gamma-Ray Flare in 2012

column densities towards these knots. Results. We measure the proper motion of 31 knots over different time scales (2, 4, 6, and 10 years). The typical tangential velocity is around 50 km/s for the 10 year base-line, but for shorter time-scales a maximum tangential velocity up to 300 km/s is found for a few knots. Based on morphology, velocity information and the locations of known protostars, we argue for the existence of at least three partly overlapping and deeply embedded flows, one Class 0 flow and two Class I flows. The multi-epoch proper motion results indicate time-variable velocities of the knots, for the first time directly measured for a Class 0 jet. We find in general higher velocities for the Class 0 jet than for the two Class I jets. While the bolometric luminosites of the three driving sources are about equal, the derived mass flow rate (dM/dt)

On the estimation of a celestial reference frame in the presence of source structure

_{\rm out}

The outburst of the blazar S4 0954+658 in 2011 March-April

is two orders of magnitude higher in the Class 0 flow than in the two Class I flows.

The Connection between the Radio Jet and the γ-ray Emission in the Radio Galaxy 3C 120 and the Blazar CTA 102

The blazar 1156+295 was active at γ -ray energies, exhibiting three prominent flares during the year 2010. Here, we present results using the combination of broad-band (X-ray through mm single-dish) monitoring data and radio-band imaging data at 43 GHz on the connection of γ -ray events to the ejections of superluminal components and other changes in the jet of 1156+295. The kinematics of the jet over the interval 2007.0–2012.5 using 43 GHz Very Long Baseline Array observations reveal the presence of four moving and one stationary component in the inner region of the blazar jet. The propagation of the third and fourth components in the jet corresponds closely in time to the active phase of the source in γ -rays. We briefly discuss the implications of the structural changes in the jet for the mechanism of γ -ray production during bright flares. To localize the γ -ray emission site in the blazar, we performed the correlation analysis between the 43 GHz radio core and the γ -ray light curve. The time lag obtained from the correlation constrains the γ -ray emitting region in the parsec-scale jet.