Speaker
Description
Millisecond pulsars (MSPs) are the most precise natural clocks in the known Universe and have proven to be powerful tools for advancing fundamental physics. Observations of MSPs at low radio frequencies (below 300 MHz) play an important role in characterising both their emission properties and the effects of the ionised interstellar medium on the received signals; both of which are critically important for high-precision pulsar timing. To date, only a small fraction of the known MSP population has been detected below 300 MHz, and nearly all previous MSP studies at these frequencies have been conducted with northern telescopes. We present the results of a census of MSPs in the Southern-sky MWA Rapid Two-metre (SMART) survey, covering declinations south of +25 deg at a centre frequency of 154 MHz. We have detected 40 MSPs, with 11 being the first published detections at low frequencies. For each MSP, we generated coherently-dedispersed full-polarimetric pulse profiles and measured flux densities and dispersion measures (DMs). We also measured Faraday rotation measures (RMs) for 25 MSPs with precisions comparable or better than MeerKAT and Murriyang/Parkes. Three MSPs exhibit apparent rotation-phase-dependent RM, two of which we show are likely due to interstellar scattering. The pulse profiles show minimal evolution in component spacing when compared with higher-frequency profiles, consistent with the emission originating from compact magnetospheres. The results of this census will be a valuable resource for planning future MSP monitoring projects at low frequencies, and will also help to improve survey simulations to forecast the detectable MSP population with the SKA-Low.
| Timeslot preferences | 20 min + questions |
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