Luminosity of SN 2023ixf in the optical and GeV bands. Top: example of a pseudobolometric luminosity (L_UBVRI) light-curve model of SN 2023ixf from Fig. 4 of Hiramatsu et al. (2023). We note that this is a conservative reference, as it is slightly lower than the bolometric luminosity derived by Bostroem et al. (2023), Teja et al. (2023), or Zimmerman et al. (2024), reaching 10⁴³ erg s⁻¹. Bottom: limits on the luminosity ratio between the optical and γ-ray bands. For comparison, the luminosity ratio from the symbiotic nova RS Oph is shown in grey (Cheung et al. 2022). Colours represent the same exposure times as in Fig. 1.