Investigating the FRB-Magnetar Link Through Low-Energy Radio Emissions

Abstract

Fast radio bursts (FRBs) are bright, millisecond-duration pulses, originating from unidentified sources. The dispersion measure (DM) of FRBs strongly suggests an extragalactic origin, however, the underlying emission mechanism and the nature of their sources remain elusive. Several theoretical models have been proposed to explain the origin of FRBs, with magnetars emerging as a prominent candidate.

We have studied magnetar XTE J1810-197 to understand the magnetar-FRB connection. We have used a large number of data sets, spanning a wide range of frequencies (300 to 6000 MHz) and covering more than 4 years from December 2018 to March 2023. These data sets were taken using the upgraded Giant Metrewave Radio Telescope (GMRT) and the Green Bank Telescope (GBT). In our study of bright single pulses, we have investigated different properties, including energetics, waiting time, and energy-time correlation, and compared them with FRBs. Additionally, we have examined how these properties evolve over time and with frequency. Our results suggest that the magnetar XTE J1810-197 can emit a FRB-like burst on a reasonably short timescale. The waiting-time distribution of the bursts from this magnetar also shows significant similarities with that of the repeating FRBs and could hold clues to why finding any underlying periodicity in the repeating FRB bursts might be hard. Correlation in time and energy of the bursts also shows similarities between magnetars and the FRBs and has implications for a starquake-like scenario to be responsible for the emission.. We will present our analyses and results in detail, which have significant implications for understanding the origin of FRBs as well as the likelihood of FRB-like emission from the Galactic magnetar population.