X-ray maps of the Orion-Eridanus superbubble (same region as in Fig. 8) in the 0.1–0.4 keV (top, contour levels: 700, 900, 1100, 1300, 1500, 1900) and the 0.5–2 keV (bottom, contour levels: 220, 300, 380, 460, 540, 620, 700) bands from the ROSAT all-sky survey (Snowden et al. 1997). The colour scale units are 10^-6 counts arcmin^-2 s^-1. The scale is linear and does not start at zero in order to de-emphasise unrelated background. The X-ray emission of the superbubble interior is delineated by shells seen in Hα (compare Fig. 8). The softer and harder X-ray bands emphasise gas at different temperature. We propose that this may relate to a global oscillation of the superbubble, similar as seen in the simulations.