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Media assistance: Helen Sim 
+61-(0)2-9372-4251 (office)
+61-(0)419-635-905 (mob.)
hsim@aao.gov.au

Artist’s illustration of the outflow in Markarian 231.
Credit: Gemini Observatory/AURA, illustration by Lynette Cook
The Gemini North telescope.
Credit: Gemini Observatory
More images of Gemini North
Timelapse movie (10.7 MB Quicktime)
Professor Sylvain Veilleux, University of Maryland.
Photo credit: Sylvain Veilleux
Assistant Professor David Rupke, Rhodes College, Tennessee.
Photo credit: David Rupke
The galaxy Markarian 231, imaged by the Hubble Space Telescope
Credit: NASA, ESA, the Hubble Heritage Team and A. Evans
Professor Joss Bland-Hawthorn, University of Sydney.
Photo credit: Chris Walsh

Contact details at end

24 February 2011

Hungry black hole destroys its own dinner


A voraciously feeding black hole creates a 'wind' that pushes its own 'food' of dust and gas out of reach, astronomers using the Gemini North telescope in Hawai'i have found.

They think this is the process that turned actively feeding black holes — common in the early universe — into the quiescent ones found in galaxies today.

"It looks like they’ve found the 'off switch' for black holes," said Professor Joss Bland-Hawthorn of the University of Sydney, who studies galactic winds.

"We've long suspected that a negative feedback process like this must be at work, but these Gemini observations are the first clear evidence of outflows that can starve a black hole of fuel."

The research will be published in the Astrophysical Journal on 10 March.

Astronomers Professor Sylvain Veilleux (University of Maryland, USA) and Dr David Rupke (Rhodes College, Tennessee, USA) studied the galaxy Markarian 231, which lies 600 million light-years away.

Markarian 231 is a 'train wreck' resulting from the collision of two galaxies. At its centre is a black hole at least ten million times the mass of the Sun, which is sucking in gas and dust from its immediate surroundings.

The black hole in Markarian 231 was known to produce narrow jets but the Gemini observations have revealed a broad outflow extending in all directions for at least 8000 light-years around the galaxy’s core.

More than one physical process is likely to be creating the outflow. One is thought to be the X-rays and gamma rays generated around the black hole, which heat up the gas in the galaxy's centre until it 'boils over'.

Gas is streaming away from the galaxy’s centre at speeds of over 1000 kilometres a second — fast enough to travel from Sydney to Perth in four seconds. The flow is sweeping away huge amounts of gas. "The fireworks of new star formation and black hole feeding are coming to an end, most likely as a result of this outflow," Rupke said.

As extreme as Markarian 231 appears, Veilleux says that it is probably not unique. In the early universe galaxies like this "are seen in large numbers and all of them may have gone through shedding events like the one we are witnessing in Markarian 231," he said.

Australia has a 6.2% share of the international Gemini partnership. Australian astronomers' access to the Gemini telescopes is managed through the Australian Gemini Office, hosted by the Australian Astronomical Observatory (AAO), Australia's national optical observatory. The AAO is part of the Commonwealth Department of Innovation, Industry, Science and Research.

 

More information

Professor Sylvain Veilleux, University of Maryland, USA
Office: +1-301-405-0282
Email: veilleux@astro.umd.edu

Assistant Professor David Rupke, Rhodes College, Tennessee, USA
Office tel: +1-901-843-3914
rupked@rhodes.edu

Professor Joss Bland-Hawthorn, University of Sydney
Mob: +61 (0)406 973 133
Office tel: +61 (0)2 9351 2621
Email: jbh@physics.usyd.edu.au

Publication

D.S. Rupke and S. Veilleux. “Integral Field Spectroscopy of Massive, Kiloparsec-Scale Outflows in the Infrared-Luminous QSO Mrk231.” Accepted for publication in the Astrophysical Journal, 10 March 2011.
www.aao.gov.au/press/mrk231/mrk231_accepted.pdf (7.2MB)

AAO media contact

Helen Sim
+61 2 9372 4251 (office in Sydney, Australia)
+61 419 635 905 (mob.)
hsim@aao.gov.au


Images

The galaxy Markarian 231, imaged by the Hubble Space Telescope
Credit: NASA, ESA, the Hubble Heritage Team and A. Evans
small (80K) www.aao.gov.au/press/mrk231/mrk231_small.jpg
large (1.9MB) www.aao.gov.au/press/mrk231/mrk231_big.jpg

Artist’s illustration of the outflow in Markarian 231.
Credit: Gemini Observatory/AURA, illustration by Lynette Cook
www.aao.gov.au/press/mrk231/art.jpg

Images of the Gemini North telescope
www.gemini.edu/gallery/v/gn/

Animation

Timelapse video of the Gemini North telescope (Quicktime 10.7 MB)
www.gemini.edu/gallery/v/Special-Images/Video/20090605_gn_stars_01.jpg.html