Spiral patterns in the central region of A1835. Left panel: X-ray residual image of the central region of A1835, smoothed with a ﹩2^{\prime\prime} ﹩ Gaussian. Pronounced spiral patterns are found. The positive-excess region extends from north to south and the negative-excess region is at the opposite side of the center. The white circle of ﹩r\lt 20^{\prime\prime} ﹩ is overlaid as a reference. The cyan cross shows the position of the BCG of A1835. The two white ellipses show the position and size of the X-ray cavities reported by McNamara et al. (2006). Right panel: same as Figure 1 but the contours of the positive (in white) and negative (in black) excess regions are overlaid. White contours show the excess levels of 100%, 90%, … , 20%, 10% of the peak value of the positive brightness residuals. The black contours are the same as the white contours, but for the negative residuals. Both of the spiral patterns are embedded in the cool core and are not distinguishable in the original X-ray image.