Broadband X-ray burst spectroscopy of the fast-radio-burst-emitting Galactic magnetar

Magnetars are young, magnetically powered neutron stars that possess the strongest magnetic fields in Universe. Fast radio bursts (FRBs) extremely intense millisecond-long pulses of primarily extragalactic origin, and a leading attribution for their genesis focuses on magnetars. A hallmark signature magnetars is emission bright, hard X-ray sub-second duration. On 27 April 2020, Galactic magnetar SGR J1935+2154 emitted hundreds within few hours. One these temporally coincided with an FRB, first known detection FRB from Milky Way. Here, we present spectral temporal analyses 24 13 hours prior to seen simultaneously Neutron Star Interior Composition Explorer (NICER) mission National Aeronautics Space Administration Fermi Gamma-ray Burst Monitor (GBM) combined energy range 0.2 keV 30 MeV. These broadband spectra permit direct comparison spectrum FRB-associated burst (FRB-X). We demonstrate all NICER GBM very similar FRB-X, but strikingly different spectrally. The singularity FRB-X perhaps indicative uncommon locale its origin. suggest this event originated quasi-polar open or closed field lines extend high altitudes. Twenty-four observed later was coincident fast (FRB). FRB-related spectrally distinct, pointing unusual point emission.