Groups & Clusters of Galaxies

Where Alice in Wonderland Meets Albert Einestein

Cheshire cat
One hundred years ago this month, Albert Einstein published his theory of general relativity, one of the most important scientific achievements in the last century.

A key result of Einstein's theory is that matter warps space-time, and thus a massive object can cause an observable bending of light from a background object. The first success of the theory was the observation, during a solar eclipse, that light from a distant background star was deflected by the predicted amount as it passed near the Sun.

Chandra Data Suggest Giant Collision Triggered "Radio Phoenix"

Abell 1033
Astronomers have found evidence for a faded electron cloud "coming back to life," much like the mythical phoenix, after two galaxy clusters collided. This "radio phoenix," so-called because the high-energy electrons radiate primarily at radio frequencies, is found in Abell 1033. The system is located about 1.6 billion light years from Earth.

Chandra Finds Evidence for Serial Black Hole Eruptions

Astronomers have used NASA's Chandra X-ray Observatory to show that multiple eruptions from a supermassive black hole over 50 million years have rearranged the cosmic landscape at the center of a group of galaxies.

Scientists discovered this history of black hole eruptions by studying NGC 5813, a group of galaxies about 105 million light years from Earth. These Chandra observations are the longest ever obtained of a galaxy group, lasting for just over a week. The Chandra data are shown in this new composite image where the X-rays from Chandra (purple) have been combined with visible light data (red, green and blue).

Dark Matter is Darker Than Once Thought

Six Galaxy Clusters*

This panel of images represents a study of 72 colliding galaxy clusters conducted by a team of astronomers using NASA's Chandra X-ray Observatory and Hubble Space Telescope. The research sets new limits on how dark matter - the mysterious substance that makes up most of the matter in the Universe - interacts with itself, as reported in the press release. This information could help scientists narrow down the possibilities of what dark matter may be.

NASA's Chandra Observatory Finds Cosmic Showers Halt Galaxy Growth

NGC 2276*

This galaxy cluster comes from a sample of over 200 that were studied to determine how giant black holes at their centers affect the growth and evolution of their host galaxy, as reported in our latest press release. This study revealed that an unusual form of cosmic precipitation enables a feedback loop of cooling and heating, stifling star formation in the middle of these galaxy clusters.

Chandra Weighs Most Massive Galaxy Cluster in Distant Universe

il Gioiello Cluster

A newly discovered galaxy cluster is the most massive one ever detected with an age of 800 million years or younger. Using data from NASA's Chandra X-ray Observatory, astronomers have accurately determined the mass and other properties of this cluster, as described in our latest press release. This is an important step in understanding how galaxy clusters, the largest structures in the Universe held together by gravity, have evolved over time.

Heating from Cosmic Chaos

Irina Zhuravleva
Irina Zhuravleva

We are pleased to welcome Irina Zhuravleva as a guest blogger today. Irina is the first author of a new paper describing a crucial role of gas turbulence in interaction between supermassive black holes and hot gas in galaxy clusters, the subject of our latest press release. Irina studied theoretical astrophysics in the department of mathematics and mechanics at Saint Petersburg State University in Russia, followed by a PhD in astrophysics at Max Planck Institute for Astrophysics in Germany. After that she moved to San Francisco area as a postdoctoral researcher at KIPAC, Stanford University.

Chaotic, turbulent flows are commonly encountered in everyday life: swirling eddies of milk poured into coffee, flickering flames of a campfire, external flows over cars and ships, white froth from breaking waves in the ocean, quaint patterns of clouds in the sky and pyroclastic flow in a volcanic eruption.

NASA's Chandra Observatory Identifies Impact of Cosmic Chaos on Star Birth

Perseus Virgo

These two Chandra images of galaxy clusters - known as Perseus and Virgo - have provided direct evidence that turbulence is helping to prevent stars from forming. These new results could answer a long-standing question about how these galaxy clusters keep their enormous reservoirs of hot gas from cooling down to form stars, as discussed in our latest press release.


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