INTEGRAL limits on past high-energy activity from FRB 20200120E in M81

TL;DR

This study used 18 years of INTEGRAL satellite data to search for high-energy X-ray bursts from FRB 20200120E in M81, setting the deepest limits to date and constraining models involving hyper-active magnetars.

Contribution

It provides the first deep hard X-ray limits on an extragalactic FRB, constraining high-energy emission models and flare rates.

Findings

No significant X-ray bursts detected from FRB 20200120E.

Set an upper limit on burst fluence of ~10^{-8} erg cm^{-2}.

Rules out frequent powerful flares from hyper-active magnetars.

Abstract

The repeating fast radio burst FRB 20200120E is located in a globular cluster belonging to the nearby M81 galaxy. Its small distance (3.6 Mpc) and accurate localization make it an interesting target to search for bursting activity at high energies. From November 2003 to September 2021, the INTEGRAL satellite has obtained an exposure time of 18 Ms on the M81 sky region. We used these data to search for hard X-ray bursts from FRB 20200120E using the IBIS/ISGRI instrument, without finding any significant candidate, down to an average fluence limit of $\sim10^{-8}$ erg cm$^{-2}$ (20-200 keV). The corresponding limit on the isotropic luminosity for a burst of duration $\Delta t$ is $\sim10^{45} \left ( \frac{10~ms}{\Delta t} \right )$ erg s$^{-1}$, the deepest limit obtained for an extragalactic FRB in the hard X-ray range. This rules out the emission of powerful flares at a rate higher than 0.1 yr$^{-1}$ that could be expected in models invoking young hyper-active magnetars.