Illustration of ejecta and radiative properties for model he12p00 at 2200 d and influenced by a magnetar power of 10³⁹ erg s⁻¹. The top row shows the mass fraction of He, C, O, Ne, Si, and Fe as a function of velocity, which reveals the location and extend of the main shells (e.g., the O/Ne/Mg shell etc). Also shown is the normalized cumulative absorbed power from the magnetar, integrated from the inner ejecta (light grey line). The middle row shows the mean ionization state for the same species and defined as ∑_iin_jⁱ⁺/∑_in_jⁱ⁺ (where n_jⁱ⁺ is the number population of ionization stage i of some species n_j; i.e., zero corresponds to the neutral state, one to once ionized etc). Also shown is the gas or free-electron temperature (light grey curve). The bottom row shows the variation of the local cooling power, as a percentage of the local total heating power, for the 17 top coolants ejecta-wide (these total cooling powers are spelled out in Table 4). The term “COL” refers to collisional excitation and “NT” to nonthermal excitation. [See Section 5.1 for discussion.]