Chandra observatory identifies impact of cosmic chaos on star birth

October 27, 2014
Chandra observations of the Perseus and Virgo galaxy clusters suggest turbulence may be preventing hot gas there from cooling, addressing a long-standing question of galaxy clusters do not form large numbers of stars. Credit: NASA/CXC/Stanford/I. Zhuravleva et al

( —The same phenomenon that causes a bumpy airplane ride, turbulence, may be the solution to a long-standing mystery about stars' birth, or the absence of it, according to a new study using data from NASA's Chandra X-ray Observatory.

Galaxy clusters are the largest objects in the universe, held together by gravity. These behemoths contain hundreds or thousands of individual galaxies that are immersed in with temperatures of millions of degrees.

This hot gas, which is the heftiest component of the aside from unseen dark matter, glows brightly in X-ray light detected by Chandra. Over time, the gas in the centers of these clusters should cool enough that stars form at prodigious rates. However, this is not what astronomers have observed in many galaxy clusters.

"We knew that somehow the gas in clusters is being heated to prevent it cooling and forming stars. The question was exactly how," said Irina Zhuravleva of Stanford University in Palo Alto, California, who led the study that appears in the latest online issue of the journal Nature. "We think we may have found evidence that the heat is channeled from turbulent motions, which we identify from signatures recorded in X-ray images."

Prior studies show , centered in large galaxies in the middle of galaxy clusters, pump vast quantities of energy around them in powerful jets of energetic particles that create in the hot gas. Chandra, and other X-ray telescopes, have detected these giant cavities before.

The latest research by Zhuravleva and her colleagues provides new insight into how energy can be transferred from these cavities to the surrounding gas. The interaction of the cavities with the gas may be generating turbulence, or chaotic motion, which then disperses to keep the gas hot for billions of years.

"Any gas motions from the turbulence will eventually decay, releasing their energy to the gas," said co-author Eugene Churazov of the Max Planck Institute for Astrophysics in Munich, Germany. "But the gas won't cool if turbulence is strong enough and generated often enough."

The evidence for turbulence comes from Chandra data on two enormous galaxy clusters named Perseus and Virgo. By analyzing extended observation data of each cluster, the team was able to measure fluctuations in the density of the gas. This information allowed them to estimate the amount of turbulence in the gas.

"Our work gives us an estimate of how much turbulence is generated in these clusters," said Alexander Schekochihin of the University of Oxford in the United Kingdom. "From what we've determined so far, there's enough turbulence to balance the cooling of the gas.

These results support the "feedback" model involving supermassive black holes in the centers of galaxy clusters. Gas cools and falls toward the black hole at an accelerating rate, causing the black hole to increase the output of its jets, which produce cavities and drive the turbulence in the gas. This turbulence eventually dissipates and heats the gas.

While a merger between two galaxy clusters may also produce , the researchers think that outbursts from supermassive are the main source of this cosmic commotion in the dense centers of many clusters.

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More information: The paper describing these results is available at: and

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1 / 5 (2) Oct 27, 2014
Really? Freakn amazing!
Da Schneib
4 / 5 (8) Oct 27, 2014
Nice piece of research, using the capabilities of the Chandra observatory to their best advantage. This is just what we put it up there to find.
Oct 28, 2014
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4.4 / 5 (7) Oct 28, 2014
@movementiseternal - if only you would take a few zillion seconds before posting your "two level smaller" inane comments... if only...
no fate
1.8 / 5 (5) Oct 28, 2014
Nice piece of research, using the capabilities of the Chandra observatory to their best advantage. This is just what we put it up there to find.

Yes, it was put up there to find hypothesis based on other hypothesis.

As supported by the "feedback" model of a theoretical object.

"Galaxy clusters are the largest objects in the universe, held together by gravity." - Hypothesis...stated as fact...tasty!

If this is "a nice peice of research", link one thing showing a "gas" at a million degrees...not plasma...gas.

Otherwise I'll take plasma and magnetic fields for 200 Alex.

Bob Osaka
not rated yet Oct 28, 2014
The caption under the images isn't grammatically correct. Adding a "why" to: galaxy clusters do not, or changing the sentence to present continuous tense: are not forming large numbers of stars, would be more clearly understood...Keep watching they may.
Any fluid dynamics folks want to dive in here? The Kolmogorov or integral length scales are difficult to nearly impossible to measure from 54 million light years. From a hose or a pipe the scales are determined by the diameter of the source. In the atmosphere they could quickly become scales in hundreds of kilometers, in galactic space it is a huge number to even wager a guess.
Remember* A complete description of turbulence remains one of the unsolved problems in physics.
Besides, the Perseus cluster holds much more interesting mysteries than billowing smoke.
not rated yet Oct 29, 2014
please refer my comment in

not rated yet Oct 29, 2014
A pity that the article offers no comparative parametric values as supportive of an empirical modelling here, instead of just linguistically phrased quantifications - it would have given more definitive insight.

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