Mon. Not. R. Astron. Soc., 437, 3236-3254 (2014/February-1)
Spectropolarimetry with the Giant Metrewave Radio Telescope at 610MHz: a case study of two southern compact group fields.
FARNES J.S., GREEN D.A. and KANTHARIA N.G.
Abstract (from CDS):
We present 610MHz spectropolarimetric images from the Giant Metrewave Radio Telescope (GMRT). We discuss the properties of the GMRT's full-polarization mode in detail and provide a technical characterization of the instrument's polarization performance. We show that the telescope can be used for wide-field spectropolarimetry. The application of Rotation Measure Synthesis results in a sensitivity at the level of tens of µJy in Faraday space. As a demonstration of the instrument's capabilities, we present observations of two southern compact groups - the Grus Quartet and USCG S063. The observations are compared with other radio and infrared data to constrain the group members' spectral index, polarization fraction and Faraday depth. Radio continuum emission is detected from all four galaxies in the Grus Quartet and one galaxy in USCG S063. Linear polarization is detected from a circumnuclear starburst ring in NGC 7552, the active nucleus of NGC 7582, and three extended radio galaxies in the background of the Grus Quartet field. These background sources allow for the classification of a Fanaroff-Riley type I and an X-shaped radio galaxy. No evidence is found for interaction with the intragroup medium in either galaxy group.