STIX spatially integrated count rate spectra and fits in time intervals I–IV (a–d). Vertical error bars represent uncertainties. Dotted and dashed lines delimit the lower and upper energies used in the spectral fitting. The values of the reduced χ² and the fitted parameters are indicated in the bottom left corners. For the thermal component vth these are emission measure [10⁴⁹ cm⁻³], temperature [keV], and relative abundance; for the non-thermal component thick2 these are total electron flux [10³⁵ electrons s⁻¹], spectral index above the break energy, break energy [keV], spectral index below the break energy, and the low-energy cutoff [keV], resp. Panels below the fits show normalised residuals, i.e. scaled by the corresponding uncertainties, as a function of energy.