We report on observations of the soft \gamma -ray repeater SGR 1935 + 2154 carried out with the INTEGRAL satellite between 2020 April 28 and May 3 , during a period of bursting activity .
Several short bursts with fluence in the range \sim 10 ^ { -7 } -10 ^ { -6 } erg cm ^ { -2 } were detected by the IBIS instrument in the 20-200 keV range .
The burst with the hardest spectrum , discovered and localized in real time by the INTEGRAL Burst Alert System , was spatially and temporally coincident with a fast radio burst detected by the CHIME and STARE2 radio telescopes at 400-880 MHz and 1.5 GHz , respectively .
The burst light curve in the 20-200 keV range shows two peaks separated by \sim 30 ms , superimposed on a broad pulse lasting \sim 0.4 s. The burst spectrum over 0.3 s is well fit with an exponentially cut-off power law with photon index \Gamma = 0.75 \pm 0.3 , e-folding energy E _ { 0 } = 52 ^ { +14 } _ { -8 } keV , and 20-200 keV flux ( 1.5 \pm 0.1 ) \times 10 ^ { -6 } erg cm ^ { -2 } s ^ { -1 } .
This is the first burst with a radio counterpart observed from a soft \gamma -ray repeater and it strongly supports the models based on magnetars that have been proposed for extragalactic fast radio bursts , despite the energy budget involved in the SGR 1935 + 2154 burst is a factor \sim 10 ^ { 8 - 9 } smaller that that of sources at distances of hundreds of Mpc .
We also estimate for SGR 1935 + 2154 a distance in the range \sim 2-7 kpc , based on the analysis of an expanding dust scattering ring seen in X-rays with the Neil Gehrels Swift Observatory XRT instrument .