Caption: "A simulated isolated stellar-mass black hole of 10 solar masses as seen from a distance of 600 km with the Milky Way in the background."
Features:
R_sch = 2.95318 km (M/M_☉) ≅ 3 km (M/M_☉) ,
and so the black hole in the image has R_sch ≅ 30 km. The Schwarzschild radius is the radius of the event horizon. See also black_hole_schwarzschild_radius_formulae.html.
Albert Einstein (1879--1955)
predicted that a point source of light
directly behind a spherically symmetric
gravitational well
would be gravitational lensed into a ring image.
Any deviation from spherically symmetry of the
gravitational well and axial symmetry of the
source
causes distortions from the perfect
Einstein ring pattern.
Near perfect Einstein rings have been observed---but
NOT
from gravitational wells that are
black hole candidates as far as knows
yours truly.
For
stellar-mass black holes,
this seems very unlikely. They are all much too far away and too small to
resolve.
But we can resolve
supermassive black holes
(i.e., their black hole shadows)
in the radio.
This was done for the first time
for the supermassive black hole
M87*
at the center of
galaxy
M87 (NGC 4486) in
2019
by the
Event Horizon Telescope (EHT).
The EHT is currently
trying to
resolve the
Sagittarius A*
which is the
supermassive black hole
at the
Milky Way center (AKA Galactic center of mass approximately).
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