Astrometric Microlensing by Primordial Black Holes with the Roman Space Telescope

• DOI: 10.3847/1538-4357/ad3243
• Publication Date: 2024-04-16T18:27:36Z
• Authors: James Fardeen; Peter McGill; Scott E. Perkins; William A. Dawson; Natasha S. Abrams; Jessica R. Lu; Ming-Feng Ho; Simeon Bird
• Keywords: Gravitational microlensing; Primordial black hole

Abstract Primordial black holes (PBHs) could explain some fraction of dark matter and shed light on many areas early-Universe physics. Despite over half a century research interest, PBH population has so far eluded detection. The most competitive constraints the comprised PBHs ( f DM ) in (10 −9 –10) M ⊙ mass ranges come from photometric microlensing bound ≲ 10 −2 –10 −1 . With advent Roman Space Telescope with its submilliarcsecond astrometric capabilities planned Galactic Bulge Time Domain Survey (GBTDS), detecting signatures will become routine. Compared microlensing, signals are sensitive to different lens masses–distance configurations contain information, making it complimentary lensing probe. At precision, typically detectable at larger lens–source separations than signals, suggesting detection channel pure events. We use simulation predict number events during GBTDS via this channel. Assuming an absolute precision floor for bright stars 0.1 mas GBTDS, we find that peaks ≈10 3 1 tapers ≈100 −4 , respectively. Accounting distinguishability stellar lenses, conclude be down −3 2 likely yielding novel constraints.