MeerKAT

Abstract:

We summarise the properties of the absorbing haloes around two high-redshift radio galaxies studied with the VLT-UVES echelle spectrograph. The absorbers in 0943 - 242 (z = 2.92) exhibit little further structure compared with previous data-the main absorber still has N(HI) similar or equal to 10(19) cm(-2)-reinforcing the picture in which the absorbing gas occupies a smooth shell beyond the emission line halo. In 0200+015 (z = 2.23) the main absorber now splits into two spatially-resolved systems with N(HI) = 4 x 10(14) cm(-2), one of which has strong CIV absorption, implying a metallicity of Z similar or equal to 10 Zcircle dot. We explain the differences between the two sources with an evolutionary scenario, invoking interaction with the expanding radio source and metal enrichment via a starburst superwind. (C) 2003 Elsevier B.V. All rights reserved.

Abstract:

We present a study of single pulses from nine bright northern pulsars to investigate the behaviour of circular polarisation, V. The observations were conducted with the Effelsberg 100-m radio telescope at 1.41 GHz and 4.85 GHz and the Westerbork radio telescope at 352 MHz. For the first time, we present the average profile of the absolute circular polarisation |V| in the single pulses. We demonstrate that the average profile of |V| is the distinguishing feature between pulse components that exhibit low V in the single pulses and components that exhibit high V of either handedness, despite both cases resulting in a low mean. We also show that the |V| average profile remains virtually constant with frequency, which is not generally the case for V, leading us to the conclusion that |V| is a key quantity in the pulsar emission problem.