Black holes -- gas blowers of the Universe

May 11, 2010
This is a false color image of the central region of a galaxy group in X-rays. The jet of matter blown out of the central black hole can be clearly identified by its radio luminosity (overlaid, purple-blue). Credit: Image: S. Giodini/A. Finoguenov/MPE

(PhysOrg.com) -- Supermassive black holes with the mass of many millions of stars have been detected at the centre of many large galaxies. A super-massive black hole acts like a lurking "monster" at the centre of the galaxy which swallows the surrounding material through the intensity of its gravitational pull.

X-ray observations indicate that a large amount of energy is produced by the in-fall of matter into a black hole, and ejected in powerful jets. Astronomers from the Max Planck Institute for have now shown that these jets eject matter not only from their host but even the gas between the galaxy group members. (Astrophysical Journal, May 1st 2010)

Astronomers have long been trying to understand how interact with the environment (the so-called feedback), but to date the process is poorly understood. Observations and simulations have shown that active galaxies transport huge amounts of material with their jets, which are particularly luminous at , into the intra-cluster gas. Signatures of this "radio-mode feedback" are observed both in radio and in X-rays.

Recent studies have shown that the amount of gas in galaxy groups, objects consisting of several galaxies bound together such as the Milky Way and the , does not add up to the amount predicted by cosmology - unlike in galaxy clusters with up to thousands of individual members. Large amounts of mechanical energy injected into the gas from the central black hole may have removed part of it. However to date this was only a hypothesis. Previous group samples were limited to a handful of nearby objects populated by low luminosity radio black holes.

Using one of the largest samples of X-ray detected groups and clusters of galaxies identified by XMM-Newton together with radio observations, a team of astronomers led by Stefania Giodini at the Max Planck Institute for Extraterrestrial Physics has studied the energetics of radio galaxy feedback in galaxy groups. In the COSMOS field, where almost 300 X-ray galaxy groups have been detected, the team has been able to show that the black hole activity in the centre of galaxy groups must have a dramatic effect on the surroundings: they eject sufficient energy to blow the intergalactic gas out of the gravitational well of the galaxy group. The mystery of the missing gas in galaxy groups is solved - and the large impact of black holes in galaxy groups demonstrated for the first time.

"In galaxy groups the gas is contained by gravity. But the black holes produce so much energy that this outweighs the capacity of the group to hold its gas," explained Stefania Giodini, the lead author of the paper. "A significant part of the gas is removed. No similar effect is observed in more massive galaxy clusters, where the huge gravitational pull restrains the gas from being removed."

"It is impressive what a significant influence radio outflows from galaxies can have on their surroundings," said Vernesa Smolčić from the California Institute of Technology, co-author of the paper. "This likely happens not only on the scales of the host galaxies of these outflows, but also on scales as large as the distance from our Milky Way to Andromeda. Radio galaxies seem to be the "trouble makers" in the Universe that can heat the gas around their host galaxies to unexpected temperatures, as well as expel a fraction of matter from galaxy groups."

Hans Böhringer, head of the Research Group for Clusters of Galaxies and Cosmology at the Max Planck Institute for Extraterrestrial Physics, also participated to this study: "In nearby clusters we can see the short term effect of the energy outbursts occasionally in the form of radio-luminous, relativistic plasma bubbles. Direct evidence for periodic outburst behaviour can only be found by looking at their effect in a large number of groups."

The enormous effect of individual galaxy nuclei is surprising even for astronomers. "I could never imagine to what a degree the black holes can displace the gas in galaxy groups," says Alexis Finoguenov from the Max Planck Institute for Extraterrestrial Physics and University of Maryland, Baltimore County, "they are the glass-blowers of the Universe".

Explore further: Quest for extraterrestrial life not over, experts say

More information: S. Giodini, et al., Radio Galaxy Feedback in X-Ray Selected Groups from COSMOS: The Effect on the ICM, The Astrophysical Journal, 714, 218, May 1st 2010

Related Stories

Chandra Sheds Light on Galaxy Collision

Mar 29, 2007

Astronomers think that there are enormous black holes at the centers of most, if not all, galaxies. These black holes, which can be millions or even billions of times more massive than the Sun, can greatly ...

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 ...

Black Hole Pumps Iron

Sep 14, 2009

(PhysOrg.com) -- This composite image of the Hydra A galaxy cluster shows 10-million- degree gas observed by Chandra in blue and jets of radio emission observed by the Very Large Array in pink. Optical data ...

How do supermassive black holes get so big?

Apr 26, 2010

(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 ...

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.

Chandra finds evidence for quasar ignition

Mar 23, 2006

New data from NASA's Chandra X-ray Observatory may provide clues to how quasars "turn on." Since the discovery of quasars over 40 years ago, astronomers have been trying to understand the conditions surrounding ...

Recommended for you

Quest for extraterrestrial life not over, experts say

Apr 18, 2014

The discovery of an Earth-sized planet in the "habitable" zone of a distant star, though exciting, is still a long way from pointing to the existence of extraterrestrial life, experts said Friday. ...

Continents may be a key feature of Super-Earths

Apr 18, 2014

Huge Earth-like planets that have both continents and oceans may be better at harboring extraterrestrial life than those that are water-only worlds. A new study gives hope for the possibility that many super-Earth ...

Exoplanets soon to gleam in the eye of NESSI

Apr 18, 2014

(Phys.org) —The New Mexico Exoplanet Spectroscopic Survey Instrument (NESSI) will soon get its first "taste" of exoplanets, helping astronomers decipher their chemical composition. Exoplanets are planets ...

User comments : 0

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

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 ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.