Replicating PSCCK2017 CMB bounds for PBH accretion

Determine the exact functional form of the energy-differential luminosity spectrum used by Poulin et al. (2017) in their Bondi–Hoyle–Lyttleton disk-accretion analysis of primordial black holes, and reproduce their Figure 2 CMB constraint under that specification to resolve the reported replication gap.

Background

The paper compares its CMB constraints on accreting primordial black holes with prior literature, including Poulin et al. (2017) (PSCCK2017), who used the Bondi–Hoyle–Lyttleton accretion model with a disk geometry and specific choices for effective velocity and energy deposition functions.

While attempting to reproduce PSCCK2017’s results, the authors found that a key input—the functional form of the luminosity spectrum—could not be precisely identified from that work, which prevented exact replication of Figure 1 and left an order-one discrepancy unresolved. Clarifying the luminosity spectrum and re-deriving the bounds would close this reproducibility gap.