GW190521: Unexpected Black Holes Collide
Explanation:
How do black holes like this form?
The two black holes that spiraled together to produce the gravitational wave event
GW190521 were not only the
most massive black holes ever seen by
LIGO and
VIRGO so far,
their masses -- 66 and 85 solar masses -- were unprecedented and unexpected.
Lower mass black holes, below about 65 solar masses are known to form in
supernova explosions.
Conversely, higher mass black holes, above about 135 solar masses, are thought to
be created by
very massive stars imploding after they use up their
weight-bearing nuclear-fusion-producing
elements.
How such
intermediate mass black holes came to exist is yet unknown, although one hypothesis
holds that they result from consecutive collisions of stars and black holes in dense
star clusters.
Featured is an illustration
of the black holes just before collision, annotated with arrows indicating their
spin axes.
In the illustration, the spiral waves indicate the production of
gravitational radiation, while the surrounding stars highlight the possibility
that
the merger occurred in a
star cluster.
Seen last year but emanating from an epoch when the universe
was only about half its present age
(
z ~ 0.8), black hole merger
GW190521
is the farthest yet detected,
to within measurement errors.
Astrophysicists:
Browse 2,200+ codes in the Astrophysics Source Code Library
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
