Variability of the Pulsed Radio Emission from the Large Magellanic Cloud Pulsar PSR J0529-6652

We have studied the variability of PSR J0529−6652, a radio pulsar in the Large Magellanic Cloud (LMC), using observations conducted at 1390 MHz with the Parkes 64 m telescope. PSR J0529−6652 is detectable as a single pulse emitter, with amplitudes that classify the pulses as giant pulses. This makes PSR J0529−6652 the second known giant pulse emitter in the LMC, after PSR B0540−69. The fraction of the emitted pulses detectable from PSR J0529−6652 at this frequency is roughly two orders of magnitude greater than it is for either PSR B0540−69 or the Crab pulsar (if the latter were located in the LMC). We have measured a pulse nulling fraction of 83.3%±1.5% and an intrinsic modulation index of 4.07 ± 0.29 for PSR J0529−6652. The modulation index is significantly larger than values previously measured for typical radio pulsars but is comparable to values reported for members of several other neutron star classes. The large modulation index, giant pulses, and large nulling fraction suggest that this pulsar is phenomenologically more similar to these other, more variable sources, despite having spin and physical characteristics that are typical of the unrecycled radio pulsar population. The large modulation index also does not appear to be consistent with the small value predicted for this pulsar by a model of polar cap emission outlined by Gil & Sendyk. This conclusion depends to some extent on the assumption that PSR J0529−6652 is exhibiting core emission, as suggested by its simple profile morphology, narrow profile width, and previously measured profile polarization characteristics.