GRB 200415A: A Short Gamma-Ray Burst from a Magnetar Giant Flare?

TL;DR

This study analyzes GRB 200415A and finds that it is most likely caused by a magnetar giant flare, supporting the idea that some short gamma-ray bursts originate from such flares rather than from compact star mergers.

Contribution

The paper provides a comprehensive analysis linking GRB 200415A to a magnetar giant flare, strengthening the connection between SGR flares and a subset of short GRBs.

Findings

GRB 200415A's properties align with magnetar giant flare signatures.

Compact star merger models struggle to explain nearby short GRBs like GRB 200415A.

Future observations are crucial to confirm the SGR giant flare origin of some short GRBs.

Abstract

The giant flares of soft gamma-ray repeaters (SGRs) have long been proposed to contribute to at least a subsample of the observed short gamma-ray bursts (GRBs). In this paper, we perform a comprehensive analysis of the high-energy data of the recent bright short GRB 200415A, which was located close to the Sculptor galaxy. Our results suggest that a magnetar giant flare provides the most natural explanation for most observational properties of GRB 200415A, including its location, temporal and spectral features, energy, statistical correlations, and high-energy emissions. On the other hand, the compact star merger GRB model is found to have difficulty reproducing such an event in a nearby distance. Future detections and follow-up observations of similar events are essential to firmly establish the connection between SGR giant flares and a subsample of nearby short GRBs.