Gamma-ray astronomy

Abstract:

A change of the component separation in the profiles of the binary pulsar PSR B1913+16 has been observed for the first time (Kramer 1998) as expected by geodetic precession. In this work we extend the previous work by accounting for recent data from the Effelsberg 100-m telescope and Arecibo Observatory and testing model predictions. We demonstrate how the new information will provide additional information on the solutions of the system geometry.

Abstract:

We report the discovery of circularly polarized radio emission from the radio-jet X-ray binary SS 433 with the Australia Telescope Compact Array. The flux density spectrum of the circular polarization, clearly detected at four frequencies between 1 and 9 GHz, is of the form V~nu-0.9+/-0.1. Multiple components in the source and a lack of very high spatial resolution do not allow a unique determination of the origin of the circular polarization or of the spectrum of fractional polarization. However, we argue that the emission is likely to arise in the inner regions of the binary, possibly via propagation-induced conversion of linear to circular polarization, and the fractional circular polarization of these regions may be as high as 10%. Observations such as these have the potential to help us investigate the composition, whether pairs or baryonic, of the ejecta from X-ray binaries.