Searching for TeV gamma-ray emission from SGR\,1935+2154 during its 2020 X-ray and radio bursting phase

Abstract

Magnetar hyperflares are the most plausible explanation for fast radio bursts (FRB) -- enigmatic powerful radio pulses with durations of several milliseconds and high brightness temperatures. The first observational evidence for this scenario was obtained in 2020 April when a FRB was detected from the direction of the Galactic magnetar and soft gamma-ray repeater SGR\,1935+2154. The FRB was preceded by two gamma-ray outburst alerts by the BAT instrument aboard the Swift satellite, which triggered follow-up observations by the High Energy Stereoscopic System (H.E.S.S.). H.E.S.S. has observed SGR\,1935+2154 for 2 hr on 2020 April 28. The observations are coincident with X-ray bursts from the magnetar detected by INTEGRAL and Fermi-GBM, thus providing the first very high energy (VHE) gamma-ray observations of a magnetar in a flaring state. High-quality data acquired during these follow-up observations allow us to perform a search for short-time transients. No significant signal at energies $E>0.6$~TeV is found and upper limits on the persistent and transient emission are derived. We here present the analysis of these observations and discuss the obtained results and prospects of the H.E.S.S. follow-up program for soft gamma-ray repeaters.

Received 2021 June 13; accepted 2021 June 28; published 2021 September 29

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Cited by in corpus (8)

• The H.E.S.S. transients follow-up system
• A MeerKAT, e-MERLIN, H.E.S.S. and Swift search for persistent and transient emission associated with three localised FRBs
• Galactic transient sources with the Cherenkov Telescope Array Observatory
• A search using GEO600 for gravitational waves coincident with fast radio bursts from SGR 1935+2154
• An updated view and perspectives on high-energy gamma-ray emission from SGR J1935+2154 and its environment
• A Very-High-Energy Gamma-Ray View of the Transient Sky
• H.E.S.S.: The High Energy Stereoscopic System
• H.E.S.S. programme searching for VHE gamma rays associated with FRBs