Multi-wavelength comparison of hot ISM plasma in the northern disc of M31 with high mass stellar and cooler ISM components. In each case, the 0.3–0.7 keV X-ray image is given in blue and excised point sources have been filled. Top-left: comparison with H I (red). Top-right: comparison with the dust content, revealed in 250 μm (red) by Herschel SPIRE and 24 μm (green) by Spitzer MIPS. Bottom-left: Hα (red) from the LGGS, which traces the warm ISM; bottom-right: location of the massive stellar population, revealed in the NUV (red) and FUV (green) by GALEX. In all panels, the extended X-ray emission regions from our spectral analysis are shown to guide the eye, with labels given in top-right only.