Theoretical studies on the memory-burden effect suggest that primordial black holes (PBHs) with masses smaller than ${10}^{15}$ grams may be viable dark matter candidates and, consequently, be potential sources of high-energy particles in the present Universe. In this paper, we investigate the evaporation of memory-burdened PBHs into high-energy gamma-rays. Differently from previous analyses, we account for the attenuation of gamma-rays caused by their interaction with background radiation at energies above ${10}^5\mathrm{GeV}$, as well as the secondary emission from the electromagnetic cascades generated during their propagation through extragalactic space. Performing a likelihood analysis with current gamma-ray data, we place new constraints on the parameter space of memory-burdened PBHs. Our results show that ultrahigh-energy diffuse gamma-ray observations set more restrictive bounds than high-energy neutrino data, particularly in scenarios with a strong memory-burden suppression of the PBH evaporation.

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• Gamma ray astronomy
• Primordial black holes