Parkes observations for project P832 semester 2012OCTS

PSR J1107-5907 is one of only a few sources known to exhibit an array of emission modulation. From moding in pulse profile shape, to complete cessation and RRAT-like emission, it has everything. It therefore can provide us with useful information about the intrinsic variability of pulsars, as well as help to bridge understanding of observed modulation timescales. It may also retain information that could elucidate the mechanisms responsible for radio emission and its cessation in pulsars. Using Parkes archival data, we have uncovered the extreme variability of PSR J1107-5907. However, the remarkable brightness of the source in one of the modes meant that it saturated the old systems. Moreover, the poor quality of this data meant that we were unable to fully characterise the emission properties of the source. Therefore, we propose new multi-frequency, single-pulse observations of PSR J1107-5907 to investigate these properties in more detail, and accurately characterise the relationship between radio emission moding and cessation in this object. Parkes is the only telescope that can observe this source and the combination of excellent frequency coverage, and polarisation capabilities, make it ideal for these proposed observations. We request 24 hours of observing time.