Groups & Clusters of Galaxies

An extraordinary ribbon of hot gas trailing behind a galaxy like a tail has been discovered using data from NASA's Chandra X-ray Observatory, as described in our latest press release. This ribbon, or X-ray tail, is likely due to gas stripped from the galaxy as it moves through a vast cloud of hot intergalactic gas. With a length of at least 250,000 light years, it is likely the largest such tail ever detected. In this new composite image, X-rays from Chandra (blue) have been combined with data in visible light from the Isaac Newton Group of Telescopes (yellow) in the Canary Islands, Spain.

This month, people around the world are celebrating the hundredth anniversary of Albert Einstein’s Theory of General Relativity (GR). Although this theory can seem esoteric, it has an important practical application: the accuracy of Global Positioning System (GPS) relies on corrections from GR.

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.

Archives, in their many forms, save information from today that people will want to access and study in the future. This is a critical function of all archives, but it is especially important when it comes to storing data from today's modern telescopes.

Galaxy clusters are often described by superlatives. After all, they are huge conglomerations of galaxies, hot gas, and dark matter and represent the largest structures in the Universe held together by gravity.

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.

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).

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.

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.

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.