Central 11 × 5 arcmin region of the unsharped masked image of NGC 253 (ratio of the Ks band image and its FMEDIAN smoothed version). On the right side of the image, the solid and dashed black lines indicate the directions of the disk and bar major axis respectively. The dashed blue annulus encircles the ring-like structure enclosing the bar. The two arrows point to the bright edges of the bar.