(a) Broken power‐law fit to the LECS + MECS + PDS data of 1997 April 16. The top panel shows the spectra from each instrument (see Table 1 for the parameters); the bottom panel shows the ratio between the spectral flux distribution and the model. (b) Same as in (a), but for the MECS + PDS data of April 16: best‐fit spectral indices at energies lower and higher than the break energy of ﹩19.5^{+4.5}_{-3.5}﹩ keV are ﹩0.58^{+0.03}_{-0.02}﹩ and ﹩0.83^{+0.08}_{-0.06}﹩, respectively (﹩\chi ^{2}_{r}=1.24﹩ for 113 degrees of freedom [dof]).