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20th of November 2023
Spectropolarimetric variability in the repeating fast radio burst source FRB 20180301A
by Kumar et al.
As the sample size of repeating fast radio bursts (FRBs) has grown, an increasing diversity of phenomenology has emerged. Through long-term multi-epoch studies of repeating FRBs, it is possible to assess which phenomena are common to the population and which are unique to individual sources. Kumar et al. present a multi-epoch monitoring campaign of the repeating FRB source 20180301A using the ultra-wideband low (UWL) receiver observations with Murriyang, the Parkes 64-m radio telescope. The observations covered a wide frequency band spanning approximately 0.7–4 GHz, and yielded the detection of 46 bursts. None of the repeat bursts displayed radio emission in the range of 1.8–4 GHz, while the burst emission peaked at 1.1 GHz. While a majority of bursts did not exhibit any polarization, those that did show a decrease in the linear polarization fraction as a function of frequency, consistent with spectral depolarization due to scattering, as observed in other repeating FRB sources. These novel observations, along with the extreme polarization properties observed in other repeating FRBs, suggest that a sub-sample of FRB progenitors possess highly dynamic magneto-ionic environments.

The image above shows a timeline of the Parkes/UWL follow-up observations of FRB 20180301A source, along with the detected bursts. Bottom Panel: Follow-up duration is displayed as shaded regions and magnified for visual representation in the left sub-plot. The burst markers are over-plotted at the zoom level, with green and orange markers indicating bursts with and without a detection of polarization, respectively. The error bars represent the spectral envelope of the individual bursts. The right sub-plot shows the histogram of spectral coverage of the repeat bursts, assuming uniform intensity. Top Panel: Follow-up duration is displayed as a bar plot binned in intervals of 10 d.

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