New evidence for a cosmological distribution of stellar mass primordial black holes

Understand

In this paper we show that to explain the observed distribution of amplitudes in a large sample of quasar lightcurves, a significant contribution from microlensing is required.

• This implies the existence of a cosmologically distributed population of stellar mass compact bodies making up a large fraction of the dark matter.
• Our analysis is based on the lightcurves of a sample of over 1000 quasars, photometrically monitored over a period of 26 years.
• The intrinsic variations in quasar luminosity are derived from luminous quasars where the quasar accretion disc is too large to be microlensed by stellar mass bodies, and then synthetic lightcurves for the whole sample are constructed with the same statistical properties.