NewsFlash: Extreme Monster Galaxy Cluster from Early Universe Discovered --Could Reveal Ultimate Secrets of Dark Matter

           


El Gordo — which means "the fat one" in Spanish — is officially known as ACT-CL J0102-4915 located located more than 7 billion light-years from Earth. Astronomers hope it could one day reveal secrets about the invisible dark matter that fills the universe. 

The monster galaxy cluster has mass about 2 quadrillion times that of the sun, making it the most massive known cluster in the observable universe. Galaxies within the cluster are concentrated in two distinct groups, and gas in El Gordo can reach super-high temperatures of nearly 360 million degrees Fahrenheit (200 million degrees Celsius), based on X-rays collected by Chandra and the European Southern Observatory's Very Large Telescope in Chile which suggests that cluster is the site of a violent merger between two galaxy clusters.

El Gordo was discovered using NASA's Chandra X-ray Observatory in space and the Atacama Cosmology Telescope in Chile. The scientists detailed their findings at the annual meeting of the American Astronomical Society during a presentation that included a separate announcement of the discovery of the most distant galaxy cluster ever seen in the early universe.

Galaxy clusters, the largest objects in the universe that are held together by gravity, form through the merger of smaller groups or sub-clusters of galaxies. Because the formation process depends on the amount of dark matter and dark energy in the universe, clusters can be used to study these mysterious phenomena.

Dark matter is material that can be inferred to exist through its gravitational effects, but does not emit and absorb detectable amounts of light. Dark energy is a hypothetical form of energy that permeates all space and exerts a negative pressure that causes the universe to expand at an ever-increasing rate.
"Gigantic galaxy clusters like this are just what we were aiming to find," said team member Jack Hughes, also of Rutgers. "We want to see if we understand how these extreme objects form using the best models of cosmology that are currently available."

Although a cluster of El Gordo's size and distance is extremely rare, it is likely that its formation can be understood in terms of the standard Big Bang model of cosmology. In this model, the universe is composed predominantly of dark matter and dark energy, and began with a Big Bang about 13.7 billion years ago.

The team of scientists found El Gordo using ACT thanks to the Sunyaev-Zeldovich effect. In this phenomenon, photons in the cosmic microwave background interact with electrons in the hot gas that pervades these enormous galaxy clusters. The photons acquire energy from this interaction, which distorts the signal from the microwave background in the direction of the clusters. The magnitude of this distortion depends on the density and temperature of the hot electrons and the physical size of the cluster.

X-ray data from Chandra and the European Southern Observatory's Very Large Telescope, an 8-meter optical observatory in Chile, show that El Gordo is, in fact, the site of two galaxy clusters running into one another at several million miles per hour. This and other characteristics make El Gordo akin to the well-known object called the Bullet Cluster, which is located almost 4 billion light years closer to Earth.
As with the Bullet Cluster, there is evidence that normal matter, mainly composed of hot, X-ray bright gas, has been wrenched apart from the dark matter in El Gordo. The hot gas in each cluster was slowed down by the collision, but the dark matter was not.

"This is the first time we've found a system like the Bullet Cluster at such a large distance," said Cristobal Sifon of Pontificia Universidad de Catolica de Chile (PUC) in Santiago. "It's like the expression says: if you want to understand where you're going, you have to know where you've been."

These results on El Gordo are being announced at the 219th meeting of the American Astronomical Society in Austin, Texas. A paper describing these results has been accepted for publication in The Astrophysical Journal.

The Daily Galaxy via http://chandra.si.edu

Comments

[peuterey jacken]

Thanks for posting Really Such Things. I should recommend your site to my friends. Cheers

[david]

go to http://tracinguniverse.blogspot.com/

[Allan W Janssen]

I was OK with molecules, and even atoms, but I got lost as soon as they announced there was even smaller stuff.
How can we be sure that you scientists aren't just pulling a collosal joke on us when you talk about quantum theory? I bet you even call it "Pulling a Planck!"

[qed]

How can we be sure that all this talk about 'universe' and 'billions' of stars is not just a colossal conspiracy of money-hungry scientists desperate to conceal the fact that the world is flat and was created in only 7 days 4000 years ago?

[Narendra Nath]

I am sorry that we miss the main point here about the primordial Big bang matter generating both the so-called dark and visible matter. The miniscule nature of the latter appears to indicate that the primordial matter was somehow generating visible matter out of the primordial matter due to some very strong interaction that could cause decay of primordial matter. The decayed product is visible matter while the major part we call dark matter is the huge residue that could not decay as that strong interaction could not last longer than a short period to cause just 4 % of visible matter. The dark matter thus got frozen as such and its nature must be non-baryonic so as not to interact with the visible matter but only provide gravitational push of the opposite kind to repell it as is being constantly observed ever since the initial moments of creation. Thus dark matter may well be quark like and not baryon like and thus makes it insensitive to all other interactions except gravity. The latter is thus a unique interaction that permits it to not get united with the other three types of interaction as its nature has changed over time and also it is different for visible and dark matter and between the two! Give a thought as we need to explain the nature as it is and not answer why it is so, if it is. Science provides answers for 'how' and not 'why'....

[smartypants]

Narendra Nath

"appears to indicate" "was somehow generating" "matter may well be". You tell it like its facts but give nothing to support it. That on top of the maybes makes a week argument. The theory sounds good though. But without why dark matter froze and maybe why it is invisible with some possible CERN backing or proof or something similar its kinda hard to believe any more than the other 100 theorys out there. Then again, just my opinion.