Future constraints on primordial black holes from XGIS-THESEUS

Abstract

Current observations allow primordial black holes (PBHs) in asteroid mass range 1017–1022 g to constitute the entire dark matter energy density (barring a small mass range constrained by 21-cm observations). In this work, we explore the possibility of probing PBHs with masses 1017–1019 g via the upcoming X/Gamma Ray Imaging Spectrometer (XGIS) telescope array on board the Transient High-Energy Sky and Early Universe Surveyor (THESEUS) mission. While our projected limits are comparable with those proposed in the literature for 1016 g<MPBH<1017 g, we show that the XGIS-THESEUS mission can potentially provide the strongest bound for 1017 g<MPBH≲3×1018 g for nonrotating PBHs. The bounds become more stringent by nearly an order of magnitude for maximally rotating PBHs in the mass range 5×1015 g<MPBH≲1019 g.