Left: far-UV image of the outer filaments from GALEX (Neff et al. 2015). The black and red contours correspond to the H i and the Herschel-SPIRE 250μm emission (Schiminovich et al. 1994; Auld et al. 2012), respectively. The blue box corresponds the region observed by Charmandaris et al. (2000) with SEST, and the dashed boxes show the field of view of MUSE observations (Santoro et al. 2015b). The circles show the position observed with APEX (CO(2−1) beam). The magenta circles show the non-detections. The regions of Table A.2 are labelled with their number. Right: map of the Herschel-SPIRE 250μm emission. The APEX spectra are overlaid in black.