From NASA Chandra: “H1821+243:: Chandra Shows Giant Black Hole Spins Slower Than Its Peers” 

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From NASA Chandra

June 30, 2022

Megan Watzke
Chandra X-ray Center, Cambridge, Massachusetts

Credit: X-ray: NASA/CXC/Univ. of Cambridge/J. Sisk-Reynés et al.; Radio: NSF/NRAO/VLA; Optical: PanSTARRS




Astronomers have gauged how fast a supermassive black hole is spinning inside a quasar 3.4 billion light years away.

Using Chandra data, they found it is rotating at about half the speed of light.

This remarkable speed is still much slower than many less massive black holes, providing clues to how this black hole grew.

Scientists think that nearly every galaxy, including the Milky Way, has a giant black hole at its center.

H1821+643 is a quasar powered by a supermassive black hole, located about 3.4 billion light years from Earth. Astronomers used /about/ 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 MNRAS. 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.

See the full article here .


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NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.
In 1976 the Chandra X-ray Observatory (called AXAF at the time) was proposed to National Aeronautics and Space Administration by Riccardo Giacconi and Harvey Tananbaum. Preliminary work began the following year at NASA’s Marshall Space Flight Center and the Harvard Smithsonian Center for Astrophysics. In the meantime, in 1978, NASA launched the first imaging X-ray telescope, Einstein (HEAO-2), into orbit. Work continued on the AXAF project throughout the 1980s and 1990s. In 1992, to reduce costs, the spacecraft was redesigned. Four of the twelve planned mirrors were eliminated, as were two of the six scientific instruments. AXAF’s planned orbit was changed to an elliptical one, reaching one third of the way to the Moon’s at its farthest point. This eliminated the possibility of improvement or repair by the space shuttle but put the observatory above the Earth’s radiation belts for most of its orbit. AXAF was assembled and tested by TRW (now Northrop Grumman Aerospace Systems) in Redondo Beach, California.

AXAF was renamed Chandra as part of a contest held by NASA in 1998, which drew more than 6,000 submissions worldwide. The contest winners, Jatila van der Veen and Tyrel Johnson (then a high school teacher and high school student, respectively), suggested the name in honor of Nobel Prize–winning Indian-American astrophysicist Subrahmanyan Chandrasekhar. He is known for his work in determining the maximum mass of white dwarf stars, leading to greater understanding of high energy astronomical phenomena such as neutron stars and black holes. Fittingly, the name Chandra means “moon” in Sanskrit.

Originally scheduled to be launched in December 1998, the spacecraft was delayed several months, eventually being launched on July 23, 1999, at 04:31 UTC by Space Shuttle Columbia during STS-93. Chandra was deployed from Columbia at 11:47 UTC. The Inertial Upper Stage’s first stage motor ignited at 12:48 UTC, and after burning for 125 seconds and separating, the second stage ignited at 12:51 UTC and burned for 117 seconds. At 22,753 kilograms (50,162 lb), it was the heaviest payload ever launched by the shuttle, a consequence of the two-stage Inertial Upper Stage booster rocket system needed to transport the spacecraft to its high orbit.

Chandra has been returning data since the month after it launched. It is operated by the SAO at the Chandra X-ray Center in Cambridge, Massachusetts, with assistance from Massachusetts Institute of Technology and Northrop Grumman Space Technology. The ACIS CCDs suffered particle damage during early radiation belt passages. To prevent further damage, the instrument is now removed from the telescope’s focal plane during passages.

Although Chandra was initially given an expected lifetime of 5 years, on September 4, 2001, NASA extended its lifetime to 10 years “based on the observatory’s outstanding results.” Physically Chandra could last much longer. A 2004 study performed at the Chandra X-ray Center indicated that the observatory could last at least 15 years.

In July 2008, the International X-ray Observatory, a joint project between European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU), NASA and Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構], was proposed as the next major X-ray observatory but was later cancelled. ESA later resurrected a downsized version of the project as the Advanced Telescope for High Energy Astrophysics (ATHENA), with a proposed launch in 2028.

European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU) Athena spacecraft depiction

On October 10, 2018, Chandra entered safe mode operations, due to a gyroscope glitch. NASA reported that all science instruments were safe. Within days, the 3-second error in data from one gyro was understood, and plans were made to return Chandra to full service. The gyroscope that experienced the glitch was placed in reserve and is otherwise healthy.

The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [NASA/ESA Hubble, NASA Chandra, NASA Spitzer, and associated programs.] NASA shares data with various national and international organizations such as from [JAXA]Greenhouse Gases Observing Satellite.