X-ray surface brightness analysis in the direction of T1. Left: Chandra X-ray image in the 0.5–2 keV band with overlaid radio contours. The surface brightness was measured from the red sector in annuli of width 2″. The fitted position of the discontinuity is shown within the sector, and is coincident with the NW cold front. Right: data points fitted with a broken power law (blue line). The red arrow indicates the peak discussed in Sec. 4.6.