code: def _load_data(self, band):
          
          d = bandpass_data_fits('sw' + self._band_map[band] + '_20041120v106.arf')[1].data
  
          # note:
          #   data.WAVE_MIN[i] < data.WAVE_MIN[i+1], but
          #   data.WAVE_MIN[i] > data.WAVE_MAX[i] (!)
          #   data.WAVE_MIN[i] = data.WAVE_MAX[i+1] (!)
  
          wmid = 0.5 * (d.WAVE_MIN + d.WAVE_MAX) # in Ångström
          df = pd.DataFrame({'wlen': wmid, 'resp': d.SPECRESP,
                             'wlo': d.WAVE_MAX, 'whi': d.WAVE_MIN})
          return df
docs: In-flight effective areas for the Swift UVOT, as obtained from the CALDB.
          See Breeveld+ 2011. XXX: confirm that these are equal-energy, not
          quantum-efficiency.