Visualization of the projected CR energy density through the simulated volume (at z = 0) of the realization with (v_st, eff, κ_eff) = (100 km s⁻¹ ,  5  ×  10²⁸ cm² s⁻¹), i.e., the fiducial set of parameters we use. The image extends 25 h⁻¹ ∼ 37 Mpc along the x- and y-axes of the plane, as well as in the projection direction. CR energy densities are as high as ≳10⁵ K cm⁻³ at the centers of galaxies, i.e., at the sites of star formation, and decay with increasing distance. Halos with multiple such sources, i.e., contributions from satellite galaxies in addition to the central, have multiple bright dots, leading to a certain degree of asymmetry in the CR energy density profile; the halo toward the lower left corner of the image is a representative example. The corresponding nonthermal CR pressure, as well as secondary effects due to associated heating plus ionization terms, has a noticeable impact on the evolution of galaxies, as we shall explore throughout the rest of this work.