Parkes observations for project P1325 semester 2024APRS_04

We request observation time with the Parkes telescope to investigate the characteristics of three "spider" millisecond pulsars (MSPs): PSR J1242-4712, PSR J2101-4802, and PSR J2129-0429. Distinguished by their remarkably compact binary orbits, these spider MSPs have an orbital period of less than a day and harbor low-mass companions (below 0.9 solar mass), all belonging to the redback spider systems. The majority of spider MSPs exhibit frequency-dependent eclipses with linear depolarization observed near their eclipse boundaries. Using the wide bandwidth of the Parkes UWL telescope (700-4000 MHz), we aim to investigate variations in the duration of eclipses within these systems across different frequencies, while also examining the fundamental eclipse mechanism. Notably, the eclipse properties of spider MSPs remain uncharted within the frequency range accessible by the Parkes UWL receiver. Our proposal aims to investigate three spider MSPs, using the wide bandwidth of Parkes UWL, specifically by modeling eclipse phase spectra in the optically thick-to-thin transitioning regime (optical depth nearly 1). Additionally, a polarization study using the UWL receiver in full polar mode will help constrain magnetic field strength variation within the eclipse region. This includes probing changes in Dispersion Measure (DM) and Rotation Measure (RM) across the pulsar's orbit, offering crucial insights into the system's specific eclipse mechanism. Therefore, we request a total of 40 hours of observing time including setup, and calibration for the investigation of the eclipse mechanisms, polarization, profile evolution, and spectra in these spider MSPs.