Different Chandra images of the core of the cluster. Upper panel: Chandra image (0.5−2 keV band) of ZwCl 235, smoothed with a Gaussian of kernel size 1.5″, with the four sectors used to study the properties of the filament, that is encompassed by sector S1, overlaid in green (see Sect. 4.7). The green cross marks the center of the BCG. Lower panels: background subtracted, exposure corrected Chandra images of the cluster core in different energy bands, used to show that the ∼1 keV thermal plasma is found predominantly along the filament. The images are smoothed with a Gaussian of kernel size 1.5″ and have matching color scales. The cyan contours in IM2 are spaced by a factor of , with the highest being 7 × 10⁻⁸ cts s⁻¹ cm⁻².