Parkes observations for project P976 semester 2018APRS_BPSR_01

Spider pulsars - black widows (BW) and redbacks (RB) - reside in incredibly tight orbits with low-mass stellar companions. The close proximity of the two orbiting bodies leads to heavy irradiation of the companion by the pulsar wind, causing material to be driven from its surface. This excess material is not gravitationally bound to the star, and the extent to which it reaches can only be constrained by observing the duration of eclipses of the radio pulsar emission that it causes. Little information about these systems is set in stone: the physical processes behind the eclipses, the dimensions, densities and magnetic properties of the eclipse medium, mass loss rates and subsequent evolution of the companions, are all unknown. Previous radio studies of a handful of spider systems have highlighted the importance of high-time resolution and large frequency coverage in constraining their properties. Measurement of the flux density, dispersion measure, rotation measure and depolarisation of the pulsars, as a function of the orbits, directly probes the eclipse process and properties of the medium causing it. All of these measurables are frequency dependent, thus with ultra-wideband observations we will have access to an unparalleled insight into spider pulsar systems. We plan to observe three eclipses for each of three BWs and two RBs in order to constrain variability between the two classes, multiple systems within each class, and the eclipses in an individual system. In addition, such observations will demonstrate and help to optimise the capabilities of the new UWL receiver.