Detecting isolated stellar-mass black holes in the absence of microlensing parallax effect

Abstract

Gravitational microlensing can detect isolated stellar-mass black holes (BHs), which are believed to be the dominant form of Galactic BHs according to population synthesis models. Previous searches for BH events in microlensing data focused on long-timescale events with significant microlensing parallax detections. Here we show that, although BH events preferentially have long timescales, the microlensing parallax amplitudes are so small that in most cases the parallax signals cannot be detected statistically significantly. We then identify OGLE-2006-BLG-044 to be a candidate BH event because of its long timescale and small microlensing parallax. Our findings have implications to future BH searches in microlensing data.

6 pages, 5 figures, MNRAS Letters accepted

References in corpus (4)

• No large population of unbound or wide-orbit Jupiter-mass planets
• OGLE-III Microlensing Events and the Structure of the Galactic Bulge
• A Search for Stellar-Mass Black Holes via Astrometric Microlensing
• PopSyCLE: A New Population Synthesis Code for Compact Object Microlensing Events

Cited by in corpus (6)

• Detecting isolated stellar-mass black holes by the Roman telescope
• The Impact of Initial-Final Mass Relations on Black Hole Microlensing
• Lens parameters for Gaia18cbf -- a long gravitational microlensing event in the Galactic plane
• Dark lenses through the dust: parallax microlensing events in the VVV
• 3D hydrodynamical simulations of the impact of mechanical feedback on accretion in supersonic stellar-mass black holes
• Identification of stellar-mass black hole binaries and the validity of linear orbital motion approximation in microlensing