Is helargest group of galaxies, the hottest, and the one that generates the most X-raysof all those discovered so far. And it has been found by US and Chilean astrophysicists with the help of the Atacama Cosmological Telescope and NASA’s Chandra X-ray Observatory. Officially known asACT-CL J0102-4915, this new group of galaxies has beennicknamed “El Gordo”by its discoverers and is located more than 7,000 million light years from Earth. The great distance at which it is located implies that scientists are observing what this group was like in its “youth”.
TheClusters of galaxies are the largest objects in the universeand they are held together by gravity. They are formed by merging smaller groups (clusters) of galaxies. Since the formation process depends on the amount of dark matter and dark energy in the universe, the groups can be used to study these mysterious phenomena.
The existence of thedark matterIt can be inferred through its gravitational effects, but it does not emit or absorb a detectable amount of light. Refering todark energy, is a hypothetical form of energy that permeates all space and exerts negative pressure that causes the universe to expand at an ever-increasing rate.
The team of scientists found “El Gordo” thanks toefecto Sunyaev-Zeldovich. According to this phenomenon, the photons from the cosmic background interact with the electrons in the hot gas that permeates these galaxy clusters. Photons gain energy from this interaction, distorting the signal from the microwave background in the direction of the clusters. The magnitude of this distortion depends on the density and temperature of the hot electrons and the physical size of the cluster.
The finding has been announced at the meeting of the American Astronomical Society and will be published in the journalThe Astrophysical Journal.
