The discovery of this cluster, known as the Phoenix Cluster, made with the National Science Foundation's South Pole Telescope, may force astronomers to rethink how these colossal structures, and the galaxies that inhabit them, evolve.
The Phoenix Cluster, shown here as it appears in microwave (orange), optical (red, green, and blue) and ultraviolet (blue) wavelengths, is forming stars at the highest rate ever observed for the middle of a galaxy cluster. The Phoenix Cluster was discovered by a collaboration of astronomers from the University of Chicago’s Kavli Institute for Cosmological Physics and elsewhere.
Credit: South Pole Telescope collaboration
New findings about an extraordinary galaxy cluster discovered by the National Science Foundation’s 10-meter South Pole Telescope, pictured here, and later followed-up by eight other world-class observatories, appear in the Aug. 16 issue of the journal Nature.
Credit: Daniel Luong-Van
Follow-up observations made in ultraviolet, optical and infrared wavelengths show that stars are forming in this object at the highest rate ever seen in the middle of a galaxy cluster. The object also is the most powerful producer of X-rays of any known cluster, and among the most massive of clusters. The data also suggest that the rate of hot gas cooling in the central regions of the cluster is the largest ever observed.
Officially known as SPT-CLJ2344-4243, this galaxy cluster has been dubbed the "Phoenix Cluster" because it is located in the constellation of the Phoenix, and because of its remarkable properties. Scientists at the University of Chicago's Kavli Institute for Cosmological Physics and their collaborators initially found the cluster, located about 5.7 billion light years from Earth, using the Sunyaev-Zel'dovich effect, the shadow that the cluster makes in fossil light leftover from the big bang.
Predicted in 1972, the effect was first demonstrated to find previously unknown clusters of galaxies by the South Pole Telescope collaboration in 2009. Observations of the effect have since opened a new window for astronomers to discover the most massive, distant clusters in the universe.
"The mythology of the Phoenix — a bird rising from the dead — is a perfect way to describe this revived object," said Michael McDonald, a Hubble Fellow at the Massachusetts Institute of Technology's Kavli Institute for Astrophysics and Space Research. McDonald is the lead author of a paper appearing in the Aug. 16 issue of the journal Nature, which presents these findings. "While galaxies at the center of most clusters have been dead for billions of years, the central galaxy in this cluster seems to have come back to life," McDonald said.
Like other galaxy clusters, Phoenix holds a vast reservoir of hot gas that contains more normal matter than all of the galaxies in the cluster combined. The reservoir of hot gas can be detected with X-ray telescopes like NASA's Chandra X-ray Observatory, and the shadow it makes in the light from the big bang can be detected with the South Pole Telescope. The prevailing wisdom had once been that this hot gas should cool over time and sink to the center of the cluster, forming huge numbers of stars.
However, most galaxy clusters have formed very few stars over the last few billion years. Astronomers think that the supermassive black hole in the central galaxy of clusters pumps energy into the system, preventing cooling of gas from causing a burst of star formation. The famous Perseus Cluster is an example of a black hole bellowing out energy and preventing the gas from cooling to form stars at a high rate.
With its black hole not producing powerful enough jets, the center of the Phoenix Cluster is buzzing with stars that are forming 20 times faster than in the Perseus Cluster. This rate is the highest seen in the center of a galaxy cluster and is comparable to the highest seen anywhere in the universe.
The frenetic pace of star birth and cooling of gas in Phoenix are causing both the galaxy and the black hole to add mass very quickly — an important phase that the researchers predict will be relatively short-lived.
"The galaxy and its black hole are undergoing unsustainable growth," said co-author Bradford Benson, a Kavli Institute Fellow at UChicago. "This growth spurt can't last longer than about a hundred million years, otherwise the galaxy and black hole would become much bigger than their counterparts in the nearby universe."
Remarkably, the Phoenix Cluster and its central galaxy and supermassive black hole are already among the most massive known objects of their type. Because of their tremendous size, galaxy clusters are crucial objects for studying cosmology and galaxy evolution and so finding one with such extreme properties like the Phoenix Cluster is important.
"The beauty of the SZ effect for cosmology is that it is as easy to detect a cluster of galaxies in the distant reaches of the observable universe as it is for one nearby," said UChicago's John Carlstrom, the S. Chandrasekhar Distinguished Service Professor in Astronomy & Astrophysics. "The magnitude of the effect depends on the mass of the object and not its distance from Earth."
Galaxy clusters contain enough hot gas to create detectable "shadows" in the light left over from the big bang, which also is known as the cosmic microwave background radiation. This light has literally travelled for 14 billion years across the entire observable universe to get to Earth. If it passes through a massive cluster on its way, then a tiny fraction of the light gets scattered to higher energies — the Sunyaev-Zel'dovich effect.
The South Pole Telescope collaboration has now completed an SZ survey of a large region of the sky finding hundreds of distant, massive galaxy clusters. Further follow-up observations of the clusters at X-ray and other wavelengths may reveal the existence of additional Phoenix-like galaxy clusters.
Also contributing observations of the Phoenix Cluster were the Gemini Observatory and the Blanco 4-meter and Magellan telescopes, all in Chile, while several space-based telescopes were used to measure the cluster's star-formation rate.
Steve Koppes | EurekAlert!
New type of low-energy nanolaser that shines in all directions
18.12.2018 | Eindhoven University of Technology
NASA research reveals Saturn is losing its rings at 'worst-case-scenario' rate
18.12.2018 | NASA/Goddard Space Flight Center
Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.
Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
18.12.2018 | Materials Sciences
18.12.2018 | Physics and Astronomy
18.12.2018 | Physics and Astronomy