Rapid Spectral Variability of a Giant Flare from a Magnetar in NGC 253

O. J. Roberts, P. Veres, M. G. Baring +18

Magnetars are slowly-rotating neutron stars with extremely strong magnetic fields ($10^{13-15}$ G), episodically emitting $\sim 100$ ms long X-ray bursts with energies of $\sim10^{4…