Panel a: light curve of GRB 170305A as measured by POLAR, with an inlay of a zoomed in version around the peak, where T = 0 s is defined as the T0 employed by Fermi-GBM in their data products for this GRB (Stanbro et al. 2017). Panel b: joint spectral fit result for 170305A. The number of counts as detected by both POLAR (blue) and the different NaI and BGO detectors of Fermi-GBM (gray tints) are shown along with the best-fitting spectrum folded through the instrument responses in yellow for POLAR data and in orange tints for the Fermi-GBM data. The residuals for both data sets are shown at the bottom of the figure.