H1821+643 is a quasar powered by a supermassive black hole, located about 3.4 billion light years from Earth. Astronomers used NASA’s Chandra X-ray Observatory to determine the spin of the black hole in H1821+643, making it the most massive one to have an accurate measurement of this fundamental property, as described in our press release. Astronomers estimate the actively growing black hole in H1821+643 contains between about three and 30 billion solar masses, making it one of the most massive known. By contrast the supermassive black hole in the center of the Milky Way galaxy weighs about four million suns.
This composite image of H1821+643 contains X-rays from
Chandra (blue) that have been combined with radio data from NSF's Karl G. Jansky Very Large
Array (red) and an optical image from the PanSTARRS telescope
on Hawaii (white and yellow). The researchers used nearly a week's worth of
Chandra observing time, taken over two decades ago, to obtain this latest
result. The supermassive black hole is located in the bright dot in the center
of the radio and X-ray emission.
Because a spinning black hole drags space around with it and allows matter to
orbit closer to it than is possible for a non-spinning one, the X-ray data can
show how fast the black hole is spinning. The spectrum — that is, the amount of
energy as a function wavelength — of H1821+643 indicates that the black hole is
rotating at a modest rate compared to other, less massive ones that spin close
to the speed of light. This is the most accurate spin measurement for such a
massive black hole.
Why is the black hole in H1821+432
spinning only about half as fast as the lower mass cousins? The answer may lie
in how these supermassive black holes grow and evolve. This relatively slow
spin supports the idea that the most massive black holes like H1821+643 undergo
most of their growth by merging with other black holes, or by gas being pulled
inwards in random directions when their large disks are disrupted.
Supermassive black holes growing in these
ways are likely to often undergo large changes of spin, including being slowed
down or wrenched in the opposite direction. The prediction is therefore that
the most massive black holes should be observed to have a wider range of spin
rates than their less massive relatives.
On the other hand, scientists expect less
massive black holes to accumulate most of their mass from a disk of gas
spinning around them. Because such disks are expected to be stable, the
incoming matter always approaches from a direction that will make the black
holes spin faster until they reach the maximum speed possible, which is the
speed of light.
A paper describing these results appears
in the Monthly Notices of the Royal Astronomical Society and is available at https://arxiv.org/abs/2205.12974 The authors are Julia Sisk-Reynes,
Christopher Reynolds, James Matthews, and Robyn Smith, all from the Institute
of Astronomy at the University of Cambridge in the UK.
NASA's Marshall Space Flight Center
manages the Chandra program. The Smithsonian Astrophysical Observatory's
Chandra X-ray Center controls science operations from Cambridge, Massachusetts,
and flight operations from Burlington, Massachusetts.
Image credit: X-ray: NASA/CXC/Univ. of
Cambridge/J. Sisk-Reynés et al.; Radio: NSF/NRAO/VLA; Optical: PanSTARRS
Read more
from NASA's Chandra X-ray Observatory.
For more Chandra images, multimedia and
related materials, visit: http://www.nasa.gov/chandra
Source: Chandra
Shows Giant Black Hole Spins Slower Than Its Peers | NASA
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