2025MNRAS.541..294H -
Mon. Not. R. Astron. Soc., 541, 294-305 (2025/July-3)
Detection of over 37 000 giant pulses per hour from PSR J1823-3021A with UHF baseband observations from MeerKAT.
HO S.C.-C., BAILES M., FLYNN C. and ABBATE F.
Abstract (from CDS):
Giant pulses (GPs) occur in high magnetic field millisecond pulsars and young Crab-like pulsars. Motivated by the fast radio bursts (FRBs) discovered in a globular cluster (GC) in the M81, we undertook baseband observations of PSR J1823-3021A, the most active GP emitter in a GC with the Meer Karoo Array Telescope (MeerKAT) ultra high frequency (UHF) band receiver (544-1088 MHz). The steep spectral index of the pulsar yields a GP rate of over 37 000 GPs h–1 with $\mathrm{ S/N}>7$, significantly higher than the 3000 GPs h–1 rate detected by previous work with the L-band (856-1712 MHz) receiver. Similarly to the previous work, we find that the GPs are (1) strongly clustered in two particular phases of its rotation, (2) well described by a power-law in terms of energies, (3) typically broad-band, and have steep spectral indices of ${\approx} {-}3$. Although the integrated pulse profile is not significantly polarized (${<} 1~{{\ \rm per\ cent}}$ linear and ${<} 3~{{\ \rm per\ cent}}$ circular), one of the brightest GPs displays notable polarization of 7 per cent (linear) and 8 per cent (circular). The high-time resolution data reveals the GPs have a range of single-peak and multipeak morphologies, including GPs with three distinct peaks. For the first time, we measured the temporal scattering of the pulsar using 49 bright, narrow, single-pulse GPs, obtaining a mean value of $5.5\pm 0.6$ $\mu$s at 1 GHz. The distinct periodicity and low polarization of GPs differentiate them from typical FRBs, although potential quasi-periodicity substructures in some GPs may suggest a connection to magnetars/FRBs.
Abstract Copyright:
© The Author(s) 2025. Published by Oxford University Press on behalf of Royal Astronomical Society.
Journal keyword(s):
pulsars: individual: J1823-3021A - globular clusters: general - fast radio bursts
Simbad objects:
11
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