Radio spectral index (α) maps of IIZw 096. The color maps in each row represent α (left panels) and its uncertainties d_α (middle panels) derived from each pixel value. The color bar on the right of each figure shows the α values from low to high. The right panel presents the histograms of the α-maps: the α, α + d_α, and α − d_α (from top to bottom). The uncertainties of α were derived from the following equation: , where the rms corresponds to the noise of the radio image, and the S_υ is the flux densities at each pixel. The top row is the result obtained from images at 1.4 GHz and 9 GHz, with restored beam 2″ × 2×. The middle row is the result obtained from images at 3 GHz and 9 GHz, with restored beam 2″ × 2″. The bottom row is obtained from images at 3 GHz and 9 GHz, with restored beam 1″ × 1″. The contour levels are magenta (1.4 GHz): 0.000335 × 1, 2, 4 mJy beam⁻¹, blue (9 GHz): 0.000069 × 1, 2, 4, 8, 16, 32 mJy beam⁻¹. green (3.0 GHz): 0.000119 × 1, 2, 4, 8, 16, 32 mJy beam⁻¹.