Full-color optical image of the plume (top panel). The luminance-filter optical image of the plume (see Sect. 2.2) excluding the pixels with uncalibrated flux larger than 0.003 (lower panel). The 3-σ (3 × 0.027 Jy beam⁻¹ km s⁻¹) H I contours in the two panels are the same as those in the lower panels in Fig. 4. The green ellipses demonstrate the condensations identified in the plume. The black solid and dashed lines in the lower panel show the loci and the averaged width for the radial profiles in Fig. 11.