Concentration C, asymmetry A, outer asymmetry OA, M₂₀, Gini(M), and excess central surface brightness | μ_0,HSB−μ_0,LSB |, for the gas in merger simulations (red) and in isolation (blue), and for the stars in merger simulations (black) and in isolation (green). The simulations shown correspond to the model-A dwarf, and encompass 14 different runs with varying satellite masses, halo concentrations, orbits, and radial extend of the gas disks with respect of the stellar disks (with R_g = R_d, 2R_d, or 4R_d) as described in Sect. 2. For more details on the simulations, see Starkenburg et al. (2016). The dotted, dashed and solid lines indicate regions where the isolated and merger systems are well separated for the stars, for the gas or for both, respectively.