Left panel: Comparison of the FAST and VLA integrated HI spectra. Only pixels with S/N > 3 are incorporated in the velocity profiles. The total HI flux densities from the two telescopes are indicated in the legend. The dashed curve shows the best-fit Gaussian profile to the FAST HI spectrum, yielding a FWHM of 28 km s⁻¹. Middle panel: Radial profiles of HI column densities derived from VLA and FAST. Radial profile derived from the VLA map that is smoothed to match the FAST beam (FWHM ∼ 3.24 arcmin) is also plotted for comparison. Right panel: HI intensity contours of VLA and FAST overplotted on the NGVS color image. The red curves denote the FAST HI (1, 3, 5, 7) × 10¹⁸ cm⁻² column density contours. The cyan curves represent the VLA HI (3, 10, 20, 30, 40) × 7 × 10¹⁸ cm⁻² column density contours. The FAST beam and the VLA synthesized beam are shown in the upper right corner as a dashed red circle and a cyan-filled ellipse, respectively. Note that the tapered natural weighted VLA HI image cube is used here.