The Square Kilometre Array (SKA)

Abstract:

We investigate circular polarization in pulsar radio emission through simultaneous observations of PSR B1133+16 at two frequencies. In particular, we investigate the association of the handedness of circular polarization with the orthogonal polarization mode phenomenon at two different frequencies. We find the association to be significant across the pulse for PSR B1133+16, making a strong case for orthogonal polarization modes determining the observed circular polarization. The association however is not perfect and decreases with frequency. Based on these results and assuming emission occurs in super-posed orthogonal polarization modes, we present a technique of mode decomposition based on single pulses. Average profiles of the polarization of each mode can then be computed by adding the individual mode-separated single pulses. We show that decomposing single pulses produces different average profiles for the orthogonal polarization modes from decomposing average profiles. Finally, we show sample single pulses and discuss the implications of the frequency dependence of the correlation of the circular polarization with the orthogonal polarization mode phenomenon.

Abstract:

We present the results of deep VLT-ISAAC Ks-band imaging of four z∼1.5 flat-spectrum quasars selected from the Parkes half-Jansky flat spectrum sample. We find that the hosts of these flat-spectrum quasars are consistent with lying on the K-z Hubble relation for radio galaxies. This implies that the flat-spectrum quasar hosts fall in line with the expectations from orientation based unified schemes and also that they contain black holes of similar mass. Moreover, the width of the Hβ broad emission line in these objects tends to be narrower than in their misaligned (low-frequency selected quasar) counterparts, implying that the width of the Hβ broad emission line depends on source inclination, at least for radio-loud quasars, in line with previous studies. © 2003 Elsevier B.V. All rights reserved.