How do supermassive black holes get so big?

Apr 26, 2010 by Lisa Zyga weblog
This illustration of the black hole in Andromeda shows an old lopsided stellar disk (red) orbiting a black hole (black dot). An inner ring of younger stars (light blue) also orbits the black hole. The stellar disks may drag swirling gas close enough to the black hole to be consumed. Credit: A. Field, NASA, ESA.

(PhysOrg.com) -- At the center of most galaxies lie supermassive black holes that can grow to become more than a billion times larger than our Sun. However, astrophysicists don’t fully understand the formation and evolution of supermassive black holes - specifically, how swirling gas from the galaxy loses its large angular momentum to allow it to be consumed by the black hole.

In a new study, astrophysicists Philip Hopkins and Eliot Quataert from the University of California, Berkeley, have proposed an explanation for how gas loses its and successfully crosses the last 30 light years to the black hole. Their idea stems from previous observations that the in the center of the is orbited by an old lopsided stellar disk. Hopkins and Quataert suggest that when gas flows toward a black hole, it initially forms this stellar disk due to gravitational instabilities.

Eventually, the stellar disk grows in size to stretch over a distance of dozens of light years from the center of the galaxy. Once it becomes large enough, its eccentric shape pulls unevenly on the incoming gas. This torque causes different gas streams to collide, reducing the gas’ momentum and allowing it to flow close enough to the black hole (less than one light year) to allow the black hole’s gravity to dominate and swallow the gas. The researchers’ simulations showed that this process could enable to consume several solar masses of gas each year, which could have helped Andromeda’s black hole to gain much of its mass.

Since Andromeda is not a unique galaxy, other supermassive black holes may also have orbiting stellar disks that transport the angular momentum of gas to the black hole’s vicinity, helping to “feed” the black hole. In addition, the eccentric stellar disk’s self-gravitational forces might reveal insight into and the cosmic X-ray background.

Explore further: First potentially habitable Earth-sized planet confirmed: It may have liquid water

More information: Philip Hopkins and Eliot Quataert. “The Nuclear Stellar Disk in Andromeda: A Fossil from the Era of Black Hole Growth.” Monthly Notices of the Royal Astronomical Society. Available at arXiv:1002.1079v2 [astro-ph.CO].
Via: New Scientist

Related Stories

Chandra data reveal rapidly whirling black holes

Jan 10, 2008

A new study using results from NASA's Chandra X-ray Observatory provides one of the best pieces of evidence yet that many supermassive black holes are spinning extremely rapidly. The whirling of these giant ...

Cygnus X-1: Still a 'Star' After All Those Years

Aug 28, 2009

Since its discovery 45 years ago, Cygnus X-1 has been one of the most intensively studied cosmic X-ray sources. About a decade after its discovery, Cygnus X-1 secured a place in the history of astronomy when ...

Black Hole Blows Bubble Between The Stars

Aug 11, 2005

A team of astronomers from The Netherlands and the UK has discovered a vast "jet-powered bubble" formed in the gas around a black hole in the Milky Way.

An Intriguing, Glowing Galaxy

May 14, 2009

A supermassive black hole may be responsible for the glowing appearance of galaxy 3C 305, located about 600 million light years away in the constellation Draco. Composite data from NASA’s Chandra X-ray Observatory ...

Galaxy Collision Switches on Black Hole

Dec 10, 2009

(PhysOrg.com) -- This composite image of data from three different telescopes shows an ongoing collision between two galaxies, NGC 6872 and IC 4970.

Recommended for you

A sharp eye on Southern binary stars

18 hours ago

Unlike our sun, with its retinue of orbiting planets, many stars in the sky orbit around a second star. These binary stars, with orbital periods ranging from days to centuries, have long been the primary ...

Hubble image: A cross-section of the universe

18 hours ago

An image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history. They range ...

Cosmologists weigh cosmic filaments and voids

22 hours ago

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

in7x
5 / 5 (5) Apr 26, 2010
Damn illustrations.

http://www.spacet...ic0512e/

More news stories

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Hubble image: A cross-section of the universe

An image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history. They range ...

Leeches help save woman's ear after pit bull mauling

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

Venture investments jump to $9.5B in 1Q

Funding for U.S. startup companies soared 57 percent in the first quarter to a level not seen since 2001, as venture capitalists piled more money into an increasing number of deals, according to a report due out Friday.