Projected gas density, O vi column density, projected temperature, and X-ray surface brightness (from left to right) within the virial radius of a galaxy at z = 0, from simulation S230D. In the O vi, temperature and X-ray panels, only the region r> 2r_opt is displayed and a Gaussian smoothing is applied. This example galaxy has M_⋆ = 3.6 × 10¹⁰ M_⊙, r_vir = 181 kpc and r_opt = 17 kpc (see Sect. 2.2 for definitions).