Median-combined images (﹩\approx 5^{\prime} \times 5^{\prime} ﹩) and radial profiles. Left column: the stacked images, after background subtraction, in units of MJy sr^–1 (see scale bars). The orange bars at the bottom indicate aperture diameter (24″) and ﹩1^{\prime} ﹩. Middle column: the radial profile of 3I in the stacked image (green; blue if the signal is above the 1σ scatter), and the mean (gray) and median (black) of the 30 brightest field stars within ﹩\lesssim 10^{\prime} ﹩. Each profile is normalized to the central pixel. The red solid and dashed lines are for ρ^−1.5 and ρ⁻¹ profiles, respectively, for the radius ρ. The nominal aperture radius (orange vertical lines) and corresponding length at 3I (title) are shown. Right column: same as the left column but convolved with a Gaussian filter with a standard deviation of 1.5 pixel for visualization. In the left and right columns, celestial north (white thick arrow), east (white thin arrow), antisolar (red solid), and antivelocity (yellow dashed) vectors are shown in the top left corner. The white and red contours (also shown in the color bar to the right of each panel) are 2σ and 5σ above the background, respectively.