Parkes observations for project P1295 semester 2023OCTS_03

We propose observing time with the Parkes telescope to investigate four ``spider" millisecond pulsars (MSPs), PSR J1048+2339 (a redback spider), PSR J1908+2105 (an MSP that occupies a region of parameter space between black widows and redbacks), PSR J2052+1219 and PSR J2256-1024 (black widow spiders). Spider MSPs are commonly seen to exhibit frequency-dependent eclipsing. Observations with wide bandwidth telescopes like Parkes UWL (700-4000 MHz) will be extremely useful to study the eclipse mechanisms in these systems. Eclipse properties of spider MSPs are hitherto unexplored at the frequency regime available with the Parkes UWL receiver. We propose to investigate a sample of 4 MSPs mentioned above (for which polarization has not been studied) with the Parkes telescope using the UWL receiver in full polar mode, which will be addressed with this proposal. One of the aims is to model the eclipse phase spectra using wideband observations of these pulsars in an optically thick-to-thin transitioning regime (optical depth nearly 1), to explore the eclipse mechanism. Observing the possible changes in rotation measure (RM) at eclipse ingress and egress will allow us to probe the magnetic field in the eclipse boundaries. We request to cover nearly one full orbit for each of these MSPs. Thus we propose 23 hours of observing time including time for setup and calibration in each epoch with the Parkes UWL receiver for the investigation of the eclipse mechanism as well as the polarization, profile evolution, and spectra of four spider MSPs.