Similar to Fig. 4, except the eROSITA image has been smoothed with a Gaussian (σ = 200″) after masking the most prominent compact sources. The image size is 200′×200′, i.e., ∼4.3 Mpc across. The excess emission has a linear size of 1–2 Mpc and extends at least to the Perseus virial radius. Two boxes show the positions of galaxies, IC310 and NGC 1264. The latter was associated with a mass concentration based on the weak lensing analysis (see HyeongHan et al. 2025).