Hawking Radiation from non-evaporating primordial black holes cannot enable the formation of direct collapse black holes

The formation of supermassive black holes (SMBHs) in the early Universe is a subject of significant debate. In this study, we examine if non-evaporating primordial black holes (PBHs) can offer a solution. By requiring that their Hawking radiation (HR) effective temperature is in the range needed to avoid the fragmentation of primordial gas halos into smaller, stellar-mass black holes, we establish initial constraints on the PBHs masses. Finally, we investigate the specific intensity of the Hawking radiation and compare it with the critical radiation needed for direct collapse black holes (DCBHs). We show that HR from non-evaporating PBHs cannot serve as the heating mechanism to facilitate the formation of the seeds for the SMBHs we observe in the high-redshift Universe.