The Planck space telescope of ESA has obtained the first conclusive evidence of the existence of a hot gas bridge connecting two separate clusters of galaxies 10 million light years.
The main goal of the Planck mission is the study of the oldest light in the universe, the Cosmic Microwave Background (CMB). As this faint radiation crosses the cosmos, it encounters different types of structures, among which include galaxies and galaxy clusters – sets of hundreds or thousands of galaxies bound together by gravity.
When cosmic background radiation interacts with the hot gas that pervades these enormous cosmic structures, alters its energy output in a very characteristic, a phenomenon known as the Sunyaev-Zel’dovich (SZ), in honor of the scientists who discovered.
Planck had used this effect to study galaxy clusters, but now it is possible to detect the faint filaments of gas that could connect all these clusters together.
In the early universe, a giant network of gaseous filaments covered the entire cosmos. Over time, they began to form galaxy clusters in denser nodes.
Astronomers have hypothesized that the place would be easier to detect these faint filaments of gas would be among the interacting galaxy clusters, where the filaments are compressed and heated slowly.
Planck has discovered a bridge connecting the hot gas Abell 399 and Abell 401 clusters, each with hundreds of galaxies inside, which shows that the hypothesis was correct.
The data collected by the European telescope XMM-Newton in the X-ray band allowed glimpsing the presence of hot gas between separate galaxy clusters billions of light years. Planck results provide the first conclusive evidence of its existence.
This is also the first time that Planck detects inter-cluster gas using a technique based on the SZ effect.
By combining data with observations Planck in band X-rays performed by the German satellite Rosat, it was determined that the temperature of the gas that forms the bridge is similar to the gas within the two clusters – the order of 80 million degrees Celsius.
Initial analyzes suggest that the gas could actually be a mixture of the tenuous strands of the great cosmic web and gas from clusters.
Detection of new bridges connecting other galaxy clusters allows more detailed analysis and understanding of these structures.
This finding demonstrates the ability of Planck to study the environment of galaxy clusters, examining its connection to the gas that permeates the cosmos and from which all groups were formed galaxies.