Multiband Detection of Repeating FRB 20180916B

TL;DR

This study presents multiband radio observations of the repeating FRB 20180916B, detecting bursts across a wide frequency range, revealing burst structures, and analyzing variations in rotation measure to inform progenitor models.

Contribution

It provides the first detection of FRB 20180916B in the 800-1000 MHz band and demonstrates the effectiveness of multiband observations for understanding FRB properties.

Findings

Detection of bursts in 300-500 MHz, 400-800 MHz, and 600-1000 MHz bands.

First-ever detection of the source in 800-1000 MHz range.

Identification of 30 μs burst structures at 800 MHz.

Abstract

We present a multiband study of FRB 20180916B, a repeating source with a 16.3 day periodicity. We report the detection of 4, 1 and 7 bursts from observations spanning 3 days using upgraded Giant Metrewave Radio Telescope (300-500 MHz), Canadian Hydrogen Intensity Mapping Experiment (400-800 MHz) and Green Bank Telescope (600-1000 MHz), respectively. We report the first-ever detection of the source in the 800-1000 MHz range along with one of the widest instantaneous bandwidth detection (200 MHz) at lower frequencies. We identify 30 $\mu$s wide structures in one of the bursts at 800 MHz, making it the lowest frequency detection of such structures for this FRB thus far. There is also a clear indication of high activity of the source at a higher frequency during earlier phases of the activity cycle. We identify a gradual decrease in the rotation measure over two years and no significant variations in the dispersion measure. We derive useful conclusions about progenitor scenarios, energy distribution, emission mechanisms, and variation of downward drift rate of emission with frequency. Our results reinforce that multiband observations are an effective approach to study repeaters and even one-off events to better understand their varying activity and spectral anomalies.