Chandra and ALMA measure speed of sloshing gas in galaxy cluster

Chandra and ALMA measure speed of sloshing gas in galaxy cluster
Credit: Institute of Astrophysics and Astronomy

Almost all galaxy clusters experience mergers. While a merger takes place, a specific spiral pattern can often be observed in X-ray images. Such a spiral feature is due to the motion of the sloshing gas induced by a merger. Observing a phenomenon similar to sloshing gas in the daily life is easy: When you swirl a wine glass containing liquid, you will see how the water rotates along with the glass. Discovering how fast the sloshing gas moves in galaxy clusters has profound astronomical meaning and therefore is of great interest to astronomers. A group of researchers from Taiwan and Japan has now measured it using a novel technique.

The lead researcher of the study, Dr. Shutaro Ueda from the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), says, "Mergers are the most important factor in the evolution of . So measuring the of sloshing gas is crucial for understanding not only the origin of the motion but also the evolution of galaxy clusters. But our knowledge about the velocity of sloshing gas is very limited due to the difficulty of measurement. So far, only a few results are reported. Thanks to high-quality Chandra X-ray and ALMA images, we succeeded in developing a to solve the puzzle by combining both images and calculating the minor perturbations of the gas in a distant galaxy ."

Measuring the moving gas has always been important to astronomers because motion is not only a basic aspect in physics but also an important characteristic of astronomical objects. The motion of astronomical objects can directly tell us what has happened in the systems. Therefore, measuring the motion is an important step toward the origins, dominating mechanisms, and the nature of the astronomical object.

The movie shows what’s happened in the galaxy cluster RXJ 1347.5-1145. i.e., before and after applying the novel technique to the X-ray surface brightness of this cluster. Credit: Chandra/Ueda et.al

In the case of galaxy clusters, many kinds of features that indicate motion of the intra-cluster medium are found. They are considered to be associated with the evolution of galaxy clusters. It is, however, hard to measure the motion of the intra-cluster medium in galaxy clusters due to the energy resolution of X-ray CCD cameras. So knowledge of the velocity field was limited to only a few samples out of hundreds of galaxy clusters—even though a number of observations have been done in the past two decades.

In addition, the measurements were restricted to the line-of-sight velocity of the intra-cluster medium, because only the Doppler effect on emission lines of highly ionized iron can be used to measure the velocity in X-rays. Recently, a new method has been proposed to measure the velocity field by focusing on the perturbation in X-ray images, but the study based on this method is limited so far. Therefore, measuring the motion of the intra-cluster medium is still one of the hottest topics, and its velocity is one of the most important physical quantities for understanding the nature of galaxy clusters.

The authors of this paper decided to measure the velocity in a luminous X-ray galaxy cluster RX J1347.5-1145 by Chandra and ALMA. Dr. Ueda added: "Of course, we need to use Chandra X-ray Observatory and ALMA, because only these two provide us with the high-angular resolution that observing distant galaxy clusters requires. The objects are so tiny on the sky."

The second author of this paper, Prof. Tetsu Kitayama at Toho University, says, "We estimated the velocity of the gas in a distant galaxy cluster by combining X-ray observation and the Sunyaev-Zel'dovich effect (SZE) data, and by solving the equation of state. In the end, we obtained direct observational evidence for the subsonic nature of the sloshing motion in a galaxy cluster 4.8 billion years away from the Earth. This means that the sloshing is rather gentle and nearly in pressure equilibrium. We expect that such measurements will become possible for a large number of galaxy clusters once the new ALMA Band 1 receivers, now being constructed under the leadership of ASIAA, are completed."

Dr. Keiichi Umetsu, a well-known cosmologist and a research fellow of ASIAA, says, "Understanding the physical state of galaxy clusters and their level of equilibrium is essential not only for the physics of galaxy clusters, but also for studies of cosmology, as they are the most massive objects to have formed in the universe. This study offers a new window into the velocity field of the gas in galaxy clusters. From now on, the novel technique developed by the team can add a new dimension of observable for astronomers to explore the nature and evolution of galaxy clusters."

The movie shows what’s happened in the galaxy cluster RXJ 1347.5-1145, i.e., before and after applying the novel technique to the data of Sunyaev-Zel’dovich effect. Credit: ALMA/Ueda et.al

Explore further

Image: Hot X-ray glow from massive cluster of galaxies

More information: Shutaro Ueda et al. A Cool Core Disturbed: Observational Evidence for the Coexistence of Subsonic Sloshing Gas and Stripped Shock-heated Gas around the Core of RX J1347.5–1145, The Astrophysical Journal (2018). DOI: 10.3847/1538-4357/aadd9d

Preprint: arxiv.org/abs/1808.09232

Provided by Institute of Astrophysics and Astronomy
Citation: Chandra and ALMA measure speed of sloshing gas in galaxy cluster (2018, October 19) retrieved 18 September 2019 from https://phys.org/news/2018-10-chandra-alma-sloshing-gas-galaxy.html
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RNP
Oct 19, 2018
Open access copy of paper here; https://arxiv.org...9232.pdf

For those interested, it is certainly worth the read.

Oct 19, 2018
Almost all galaxy clusters experience mergers.

Nonsense, in the first line. No need to read the rest.

Oct 19, 2018
Almost all galaxy clusters experience mergers.

Nonsense, in the first line. No need to read the rest.


Who cares what a crank reads or doesn't read?

Oct 19, 2018
A slosh of amber nectar
With all that plasma gravitational constrained it should slosh around like the amber nectar, just when you need a good dollop of the DARK crumbly stuff to pin those plasmatic ions down, it's gone all shy again!
.

Oct 20, 2018
While a merger takes place, a specific spiral pattern can often be observed in X-ray images. Such a spiral feature is due to the motion of the sloshing gas induced by a merger.

The plasma ignoramuses talking about gases sloshing about due to gravity, someone should tell them that's not how plasma works. Wait, they are not concerned about reality when they can play their computer games using their pseudoscientific maths claptrap.

Oct 20, 2018
For tuxedo, you gotta understand. Those big words in the first sentence scared him off!

cant and granny, truly, a marriage made in Bedlam!

Oct 20, 2018
While a merger takes place, a specific spiral pattern can often be observed in X-ray images. Such a spiral feature is due to the motion of the sloshing gas induced by a merger.

The plasma ignoramuses talking about gases sloshing about due to gravity, someone should tell them that's not how plasma works. Wait, they are not concerned about reality when they can play their computer games using their pseudoscientific maths claptrap.


Sorry? I think it is well known that the plasma ignoramuses are most definitely EUists, correct? Not a single plasma physicist within their ranks, is there? Nor astrophysicist, for that matter. So, woo boy - who would you propose to analyse this data? Thornhill and Scott? Hahahahahahahaha!

Oct 20, 2018
who would you propose to analyse this data?

Certainly not astrophysicists;

"Students using astrophysical textbooks remain essentially ignorant of even the existence of plasma concepts, despite the fact that some of them have been known for half a century. The conclusion is that astrophysics is too important to be left in the hands of astrophysicists who have gotten their main knowledge from these textbooks. Earthbound and space telescope data must be treated by scientists who are familiar with laboratory and magnetospheric physics and circuit theory, and of course with modern plasma theory." Hannes Alfvén

Oct 20, 2018
who would you propose to analyse this data?

Certainly not astrophysicists;

"Students using astrophysical textbooks remain essentially ignorant of even the existence of plasma concepts, despite the fact that some of them have been known for half a century. The conclusion is that astrophysics is too important to be left in the hands of astrophysicists who have gotten their main knowledge from these textbooks. Earthbound and space telescope data must be treated by scientists who are familiar with laboratory and magnetospheric physics and circuit theory, and of course with modern plasma theory." Hannes Alfvén


Give up your pathetic deification of Alfven's ancient dogma. You haven't got anybody remotely qualified, have you? Why is that?

Oct 20, 2018
You haven't got anybody remotely qualified, have you?

Birkeland got it a 100-years ago, you and the plasma ignoramuses still fumble about with faerie dust.

"According to our manner of looking at the matter, every star in the universe would be the seat and field of activity of electric forces of a strength that no one could imagine.
We have no certain opinion as to how the assumed enormous electric currents with enormous tension are produced, but it is certainly not in accordance with the principles we employ in technics on the earth at the present time. One may well believe, however, that a knowledge in the future of the electrotechnics of the heavens would be of great practical value to our electrical engineers.
It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. We have assumed that each stellar system in evolutions throws off electric corpuscles into space..."

Oct 20, 2018
Lost in Birkland currants
While a merger takes place, a specific spiral pattern can often be observed in X-ray images. Such a spiral feature is due to the motion of the sloshing gas induced by a merger.

The plasma ignoramuses talking about gases sloshing about due to gravity, someone should tell them that's not how plasma works. Wait, they are not concerned about reality when they can play their computer games using their pseudoscientific maths claptrap.

CD85, Lost in Birkland currants - and it appears you're also out the loop cantdrive and after all those years spent locked in battle with JD, such a shame!

Oct 21, 2018
Alfven and Birkeland both politely requested that the woo frauds cease and desist from misrepresenting their work. And stealing unearned credit from the Real Scientists accomplishments.

Yeah? Well I ain't so polite as to not publicly accuse the various cults of EU/Aether/theosophist/Mesmerist gibberish of their complete lack of morals or ethics.

After centuries of gulling the simpletons? They have no original discoveries or inventions not stolen from someone else.

Oct 21, 2018
They have no original discoveries or inventions not stolen from someone else.

It's called "standing on the shoulders of giants". And all involved are properly citing the people from which they are gleaning the information.
Lest we not forget, Einstein was a master plagiarist, nary an original idea of his own yet claimed them to be his own.

Oct 22, 2018
And again cant. What have you invented?

What have you or any of your fellow cultists ever accomplished that was original ir creative?

Ever?

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