ESA's Planck space telescope has made the first conclusive detection of a bridge of hot gas connecting a pair of galaxy clusters across 10 million light-years of intergalactic space.
Planck's primary task is to capture the most ancient light of the cosmos, the Cosmic Microwave Background, or CMB. As this faint light traverses the Universe, it encounters different types of structure including galaxies and galaxy clusters – assemblies of hundreds to thousands of galaxies bound together by gravity.
If the CMB light interacts with the hot gas permeating these huge cosmic structures, its energy distribution is modified in a characteristic way, a phenomenon known as the Sunyaev–Zel'dovich (SZ) effect, after the scientists who discovered it.
This effect has already been used by Planck to detect galaxy clusters themselves, but it also provides a way to detect faint filaments of gas that might connect one cluster to another.
In the early Universe, filaments of gaseous matter pervaded the cosmos in a giant web, with clusters eventually forming in the densest nodes.
Much of this tenuous, filamentary gas remains undetected, but astronomers expect that it could most likely be found between interacting galaxy clusters, where the filaments are compressed and heated up, making them easier to spot.
Planck's discovery of a bridge of hot gas connecting the clusters Abell 399 and Abell 401, each containing hundreds of galaxies, represents one such opportunity.
The presence of hot gas between the billion-light-year-distant clusters was first hinted at in X-ray data from ESA's XMM-Newton, and the new Planck data confirm the observation.
It also marks Planck's first detection of inter-cluster gas using the SZ effect technique.
By combining the Planck data with archival X-ray observations from the German satellite Rosat, the temperature of the gas in the bridge is found to be similar to the temperature of the gas in the two clusters – on the order of 80 million degrees Celsius.
Early analysis suggests the gas could be mixture of the elusive filaments of the cosmic web mixed with gas originating from the clusters.
A more detailed analysis and the possible detection of gas bridges connecting other clusters will help to provide a more conclusive answer.
The new finding highlights the ability of Planck to probe galaxy clusters to their outskirts and beyond, examining their connection with the gas that permeates the entire Universe and from which all groups of galaxies formed.
European Space Agency: http://www.esa.int
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Astronomers have shown that dead stars known as white dwarfs can re-ignite and explode as supernovas.
Two satellites destined for the Galileo global positioning network may have to burn most of their fuel to get back into formation, or be replaced
Eavesdropping on Saturn's rings has given us clues about surprises in the gas giant's interior
NASA will build a huge new heavy-lift Space Launch System rocket to propel astronauts on flights to nearby asteroids and eventually Mars
They call it "Sparky"
Mouse astronauts are joining the research carried out at the International Space Station.
US defence giant Lockheed Martin is teaming up with an Australian technology firm to track space debris that can damage multi-billion dollar satellites.
Europe's Rosetta mission, which aims to put a robot on a comet in November, has identified five potential sites for the touchdown.
The New Horizons spacecraft is on its way to Pluto
Russian cosmonaut Vladimir Solovyev says the plankton were blown up into space by air currents on earth