Closing the Mass Window for Stupendously Large Black Holes

Abstract

We show that primordial black holes (PBHs) in the $\text{Stupendously Large Black Hole}$ mass range ($M\gtrsim 10^{11}{M}_{\odot }$) produce isocurvature perturbations exceeding current $\text{Planck}$ Cosmic Microwave Background limits, thereby excluding them as a significant dark matter component.

Comments: 4 pages, 2 figures