X-ray surface brightness images extracted from simulations of models B_1 and A_1, for different viewing directions. The box size is 1.6 Mpc and time is in Gyr, with t = 0 at the pericenter passage. In each panel the epoch, t, is when the projected distance, d_DM, between the mass centroids is approximately d_DM ∼ 700 kpc; the orientation angles {α, i} of the merging plane are defined in Sect. 2.4. In each panel the log-spaced contour levels of the projected X-ray surface brightness (red) and mass density (white) are overlaid. From the inside to outside, the contour levels of the X-ray surface brightness and of the surface mass density are: (6.6, 4.4, 2.9, 1.9, 1.2) × 10⁻¹ counts arcsec⁻² and (5.6, 3.1, 1.8) × 10⁻¹ gr cm⁻². The crosses indicate the projected spatial locations of the mass (green) and X-ray surface brightness (red) centroids; the yellow cross shows the position of the SZ centroid. The maps can be directly compared with Figs. 1 and 3 of ZYL15, the orientation along the viewing direction of the merging plane in the sky being the same. In particular, the mid panels of models A_1 and B_1 correspond to the fiducial models A and B of ZYL15 (see their Table 2). For these models, the X-ray luminosity in the 0.5 − 2 keV band is given in units of 10⁴⁵ ergs⁻¹. For the fiducial model B_1 (top mid panel), the dashed orange line shows the location and orientation of the spatial region used to extract the X-ray surface brightness profile. This model is chosen as the baseline model of the simulations.