Scientists Surprised by Relentless Cosmic Cold Front

This winter has brought many intense and powerful storms, with cold fronts sweeping across much of the United States. On a much grander scale, astronomers have discovered enormous “weather systems” that are millions of light years in extent and older than the Solar System.

The researchers used NASA’s Chandra X-ray Observatory to study a cold front located in the Perseus galaxy cluster that extends for about two million light years, or about 10 billion billion miles.

Galaxy clusters are the largest and most massive objects in the Universe that are held together by gravity. In between the hundreds or even thousands of galaxies in a cluster, there are vast reservoirs of super-heated gas that glow brightly in X-ray light.

The cold front in the Perseus cluster consists of a relatively dense band of gas with a “cool” temperature of about 30 million degrees moving through lower density hot gas with a temperature of about 80 million degrees. The enormous cold front studied with Chandra formed about 5 billion years ago and has been traveling at speeds of about 300,000 miles per hour ever since. Surprisingly, the front has remained extremely sharp over the eons, rather than becoming fuzzy or diffuse.

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Credits: NASA/CXC/GSFC/S. Walker, ESA/XMM, ROSAT

A gigantic and resilient “cold front” hurtling through the Perseus galaxy cluster has been studied using data from NASA’s Chandra X-ray Observatory.

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Combining data from NASA's Chandra X-ray Observatory with radio observations and computer simulations, scientists have found a vast wave of hot gas in the nearby Perseus galaxy cluster. Spanning some 200,000 light-years, the wave is about twice the size of our own Milky Way galaxy.

The researchers say the wave formed billions of years ago, after a small galaxy cluster grazed Perseus and caused its vast supply of gas to slosh around an enormous volume of space.

Galaxy clusters are the largest structures bound by gravity in the universe today. Some 11 million light-years across and located about 240 million light-years away, the Perseus galaxy cluster is named for its host constellation. Like all galaxy clusters, most of its observable matter takes the form of a pervasive gas averaging tens of millio ns of degrees, so hot it only glows in X-rays.

Chandra observations have revealed a variety of structures in this gas, from vast bubbles blown by the supermassive black hole in the cluster's central galaxy, NGC 1275, to an enigmatic concave feature known as the "bay."

 

Astronomers in England have discovered a singing black hole in a distant cluster of galaxies. In the process of listening in, the team of astronomers not only heard the lowest sound waves from an object in the Universe ever detected by humans, but they've also discovered an important clue about the formation of galaxy clusters -- the largest structures in the cosmos.

 

Observatory coupled with a computer simulation. The simulation shows the gravitational disturbance resulting from the distant flyby of a galaxy cluster about a tenth the mass of the Perseus cluster.

The event causes cooler gas at the heart of the Perseus cluster to form a vast expanding spiral, which ultimately forms giant waves lasting hundreds of millions of years at its periphery. Merger events like this are thought to occur as often as every three to four billion years in clusters like Perseus.