Pulsars, transients and relativistic astrophysics

Abstract:

We present polarization data for 32 mainly southern pulsars at 8.4 GHz. The observations show that the polarization fraction is low in most pulsars at this frequency except for the young, energetic pulsars which continue to show polarization fractions in excess of 60 per cent. All the pulsars in the sample show evidence for conal emission with only one third also showing core emission. Many profiles are asymmetric, with either the leading or the trailing part of cone not detectable. Somewhat surprisingly, the asymmetric profiles tend to be more polarized than the symmetrical profiles. Little or no pulse narrowing is seen between 1 and 8.4 GHz. The spectral behaviour of the orthogonal polarization modes and radius to frequency mapping can likely account for much of the observational phenomenology. Highly polarized components may orginate from higher in the magnetosphere than unpolarized components.

Abstract:

Chandra observations of 3C432, 3C 191 and B2 0902+34 are presented as part of an ongoing search for inverse-Compton scattering of the cosmic microwave background (CMB) from high redshift radio sources (Schwartz, 2000). The energy density of the CMB increases with redshift, z, as (1 + z)4, so the relatively high redshift of these powerful radio galaxies makes them good candidates for detecting extended inverse-Compton scattering along the radio jet axis: we do indeed detect radio-aligned X-ray emission.