H i column density contours from Lelli et al. (2012), with 2′′ resolution (beam size in the bottom left). Contours are drawn for 3 (dashed), 6, 9, 12, and 15 × 10²¹ cm^-2. The largest red circle shows the PACS beam at 157 μm ([C ii]) and the smallest red circle shows the beam at 63 μm ([O i]). Both beams are centered at the emission centroid derived by the PACS optimal extraction method (Sect. 3.1.1). The green cross shows the location of the X-ray point source (Sect. 3.3). The background image is HST/ACS F555W. The NW region coincides with an H i hole. The H i column density peak lies between NW and SE.