Left: spectral index map. Spectral indices were computed by fitting a single power-law radio spectrum through the fluxes at 241, 610, 1382, and 1714 MHz. Solid contours are from the 1382 MHz WSRT map and drawn at levels of [1,4,16,64,...] × 6σ_rms. The resolution of the map is 23.5″ × 17.0″. Right: spectral index uncertainty map. The map is computed on the basis of σ_rms values for the individual maps.