Point-to-point correlation between radio spectral index and X-ray temperature for Abell 2142. The upper row shows X-ray temperature maps derived from Chandra (left) and XMM-Newton (right) observations, with contours showing 143 MHz LOFAR data at 25 arcsec resolution. Coloured boxes show the regions covering H1 (yellow) and H2 (cyan) used to probe the α/T_X correlation. The lower panels show the point-to-point correlation between radio spectral index and X-ray temperature measured by Chandra (left) and XMM-Newton (right). The dashed lines indicate the best-fit relation, with the shaded region denoting the 1σ uncertainty; the slopes are shown in the inset in each subplot.