tokens: pressure wherever a shock is detected (see Fig. 2 ) since shocks are the acceleration sites for CRs. The following conditions (Gupta, Nath Sharma 2018b ) have been used to detect whether a particular region within the simulation box is shocked or not: ; Δ x |∇ p |/ p > δ tolerance ; ∇ T .∇ρ > 0. Figure 2. Comparison of density and thermal pressure between TH and TH+CR runs for M12 galaxy at ≈20 Myr simulation time. The three sets of plots (from left) are for SFR = 0.1, 1, and 10 . We also show the CR pressure in a separate plot. Green dots show the shock locations. In the TH+CR runs, these are the locations where CR energy is injected. For all our simulations, we have used δ tolerance = 0.5. Wherever a shock is detected, we redistribute the total pressure between thermal and CR component following the CR pressure component fraction w = p cr /( p th + p cr ). In all our models, we have used w = 0.2. 3 RESULTS To understand the properties of outflowing gas between the models with and without CRs, we investigate (i) the morphology of the outflowing gas, (ii) outer shock position, (iii) mass-loading factor, and (iv) temperature distribution of the gas. These quantities have been used in previous studies to quantify the dynamical impact of CRs. Here we present the results from our simulations of three different galaxies with halo masses of , and using three different constant SFRs: 1 0.1, 1, and 10 . To represent runs with and without CRs, we have used two different labels: ‘TH+CR’ and ‘TH’, respectively. Note that we have used our simulation for M11 galaxy as the fiducial run. The used parameters are given in Table 1 . 3.1 Outflow morphology In Figs 2 , 3 , and 4 , we show the morphology of outflowing gas for three different halo masses for TH and TH+CR runs. For all runs, we find that the shape of the outflow is nearly spherical in nature. For M8, the shape is expected to be more spherical because, in this case, the galactic disc is much smaller than the outflow length-scale and the disc is not included in our simulation. For all cases, the forward and reverse shocks are prominently distinguishable, except for SFR = 0.1 in M12 galaxy. In this case, the outflow has an irregular shape and does not show a prominent reverse shock; the locations of shocks are rather distributed inside the bubble. This can be seen from the shock locations, as displayed by the green dots in the second rows of Figs 2 , 3 , and 4 . Figure 3. Same as Fig. 2 , for M vir = 10 11 M ⊙ . Figure 4. Same as Fig. 2 , for M vir = 10 8 M ⊙ . For SFR = 0.1 (first column of Figs 2 , 3 , and 4 ), a comparison of different snapshots among three haloes shows that for M12 galaxy, before the outflow breaks out of the central region, an acoustic wave propagates from the central region. This can be understood as follows. In our set-up, CRs are initially confined in the galactic disc and the halo has very low CR pressure. Due to the pressure gradient, the CRs start to diffuse out of the disc
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