arXiv subjects

Izabela Owsianik

Publications and source records attributed to Izabela Owsianik.

3 recordsLinked to original sources

arXiv2002

1245+676 - a CSO/GPS source being an extreme case of a double-double structure

AGN with the so-called `double-double' radio structure have been interpreted as restarted AGN where the inner structure is a manifestation of a new phase of activity which happened to begin before the outer radio lobes resulting from the previous one had faded completely. The radio galaxy 1245+676 is an extreme example of such a double-double object - its outer structure, measuring 970 h^{-1} kpc, is five orders of magnitude larger than the 9.6 h^{-1} pc inner one. We present a series of VLBI observations of the core of 1245+676 which appears to be a compact symmetric object (CSO). We have detected the motion of the CSO's lobes, measured its velocity, and inferred the kinematic age of that structure.

astro-ph↗

arXiv1998

First detection of hotspot advance in a Compact Symmetric Object. Evidence for a class of very young extragalactic radio source

We present the results of multi-epoch global VLBI observations of the Compact Symmetric Object (CSO), 0710+439 at 5 GHz. Analysis of data spread over 13 years shows strong evidence for an increase in the separation of the outer components at a rate of $0.251 \pm 0.029 h^{-1}c$. Dividing the overall size of 86.8 $h^{-1}$pc by this separation rate implies an estimated kinematic age of only $1100 \pm 100$ yrs. After taking into account possible temporal variations in hotspot advance speeds due to cloud collisions or hydrodynamic instabilities we argue that the upper limit to the age of 0710+439 is most likely within a factor of 2 of this estimate and certainly within a factor of 10 (i.e. $<11 000$ yrs). This result therefore strongly supports the idea that Compact Symmetric Objects are very young radio-loud sources. Furthermore the large radiative efficiency we calculate for 0710+439 is consistent with strong negative luminosity evolution as CSOs grow in size and with them evolving into classical double sources.

astro-ph↗

arXiv1998

Renewed Radio Activity of Age 370 years in the Extragalactic Source 0108+388

We present the results of multi-epoch global VLBI observations of the Compact Symmetric Object (CSO) 0108+388 at 5 GHz. Analysis of data spread over 12 years shows strong evidence for an increase in the separation of the outer components at a rate of $0.197\pm0.026 h^{-1}c$. Given an overall size of 22.2 $h^{-1}$pc this implies a kinematic age of only $367\pm48$ yrs. This result strongly supports the idea that radio emission in Compact Symmetric Objects arises from recently activated radio sources. The presence of weak radio emission on kpc-scales in 0108+388 suggests recurrent activity in this source, and that we are observing it just as a new period of activity is beginning.

astro-ph↗