Panel a: light curve of GRB 170101A as measured by POLAR where T = 0 s is defined as the T0 defined by Swift-BAT for this GRB. Panel b: joint spectral fit result for 170101A. The number of counts as detected by both POLAR (blue) and Swift-BAT (red) are shown along with the best fitting spectrum folded through the instrument responses in yellow for POLAR data and in brown for Swift-BAT data. The residuals for both data sets are shown at the bottom of the figure.