Establish the long-term survival and properties of primordial-black-hole circumstellar disks

Establish whether circum-primordial-black-hole disks can survive over galactic timescales and determine their specific physical properties.

Background

The paper considers the possibility that primordial black holes acquired disk-like accretion flows from baryonic matter after recombination and during the cosmic dark ages. Existing studies primarily examine the effects of active accretion disks on cosmic microwave background constraints, rather than whether accretion ultimately consumes the disk or leaves a cold, quiescent remnant.

The authors note that the long-term evolution depends on uncertain viscosity, ionization, and accretion processes. Persistent disks could affect microlensing lightcurves through extinction or refraction, making their survival and physical composition relevant to both primordial-black-hole abundance studies and future surveys.