Fast Radio Transients in the nearby Universe

Abstract:

Motivated by the discovery of a repeating FRB associated with a globular cluster in the nearby galaxy M81, this talk explores the origins of fast radio transients in old stellar environments and examines the relationship between FRBs and giant radio pulses (GPs) from neutron stars. Using MeerKAT ultra-high frequency (UHF) baseband observations of the millisecond pulsar PSR J1823-3021A in the globular cluster NGC 6624, we detect more than 3.7×10^4 GPs per hour, establishing it as one of the most prolific GP emitters known. Although the pulses exhibit complex temporal and spectral structures, their energetics, periodicity, and statistical properties distinguish them from FRBs, suggesting that GPs are unlikely to be direct low-energy analogues of the FRB population. We also investigate scintillation and coherent descattering, demonstrating the feasibility of recovering intrinsic pulse structures from giant pulses in J1823-3021A. Extending this work to extragalactic systems, we conduct a deep FAST search for FRBs from globular clusters in the nearby elliptical galaxy M49 (NGC 4472), covering ~4000 globular clusters. No FRBs are conclusively detected, yielding stringent upper limits on FRB activity in globular clusters. Lastly, in this talk, I will briefly present the current status of the Bustling Universe Radio Survey Telescope in Taiwan (BURSTT), which is a dedicated survey aiming to search for FRBs in the nearby universe with its extremely wide field of view (~10,000 square degrees).

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