VLBA polarimetric observations of the CSS quasar 3C 147

¹ Istituto di Radioastronomia – INAF, via Gobetti 101, 40129, Bologna, Italy e-mail: rossetti@ira.inaf.it
² Dipartimento di Astronomia, Università degli Studi, via Ranzani 1, 40127 Bologna, Italy
³ Los Alamos National Laboratory, Los Alamos, NM 87545, USA
⁴ Arecibo Observatory, HC3 Box 53995, Arecibo 00612, Puerto Rico
⁵ National Centre for Astrophysics, TIFR, Post Bag 3, Ganeshkhind, Pune 411 007, India

Received: 20 October 2008
Accepted: 24 April 2009

Abstract

Aims. We report new VLBA polarimetric observations of the compact steep-spectrum (CSS) quasar 3C 147 (B0538+498) at 5 and 8.4 GHz.

Methods. By using multifrequency VLBA observations, we derived milliarcsecond-resolution images of the total intensity, polarisation, and rotation measure distributions, by combining our new observations with archival data.

Results. The source shows a one-sided structure, with a compact region, and a component extending about 200 mas to the south-west. The compact region is resolved into two main components with polarised emission, a complex rotation measure distribution, and a magnetic field dominated by components perpendicular to the source axis.

Conclusions. By considering all the available data, we examine the possible location of the core component, and discuss two possible interpretations of the observed structure of this source: core-jet and lobe-hot spot. Further observations to unambiguously determine the location of the core would help distinguish between the two possibilities discussed here.