Time evolution (from left to right; the snapshot time is indicated on the top of each column) of X-ray properties of simulation 3S1-hr, featuring 3 massive stars at about 30 pc distance from each other. From top to bottom, the plots show column density distributions of all gas (the three massive stars are indicated as white stars), and of X-ray-emitting gas at temperatures of 0.05–1 keV, 1–2 keV, 2–4 keV and 4–10 keV. The colour bar gives values relevant to the X-ray panels, but the colour scale is the same for the total gas column. The left column shows the superbubble in the Wolf-Rayet phase of the central, most massive star. The middle columns display two different snapshots shortly after the first supernova, first with prominent high energy and then with very strong soft emission, when the shock approaches the shell. Right column: 0.6 Myr after the final supernova, which occurred off-centre, the hot gas performs global oscillations, which leads to the different morphologies in the different bands. See Table 2 for exact snapshot times and corresponding X-ray luminosities. (Online movie.)