Mass Measurement of Isolated Black Hole Candidate MOA-2019-BLG-284L via Lensed Image Separation
Abstract
We propose a novel method to measure the mass of the MOA-2019-BLG-284 microlens, which is a black hole candidate due to its extremely long Einstein radius crossing time of 890 days and its low microlensing parallax amplitude. The microlensing parallax is well measured due to the multiyear event duration, and the duration of the event is long enough to suggest a lens mass of more than 20 solar masses. This event will be passing through its peak magnification during 2020, which should allow the measement of a slight image elongation due to the separation of the two relatively bright lensed images. Furthermore, the direction of this elongation will rotate during the year, with a total rotation of about 53 degrees over the course of our proposed observations from March to September, 2020. This rotation will confirm that the image elongation is indeed a gravitational lensing effect. If successful, these observations will determine the lens mass and open a new window on the, as yet unmeasured, isolated black hole population of our Galaxy. This method can be futher exploited by JWST, which shoud be able to make such measurements with higher sensitivity than HST.
- Publication:
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HST Proposal
- Pub Date:
- February 2020
- Bibcode:
- 2020hst..prop16067B