Astronomers: «the dead» galaxies exist from the very birth of the Universe

© Illustration RIA Novosti . Alina Paladinette galaxy already existed in the first age of the UniverseAstronomers: «the dead» galaxies exist from the very birth of the Universe© Illustration RIA Novosti . Alina Polyanina

Observations of the oldest galaxies of the Universe have helped scientists to find out what «dead» galaxy, not able to form new stars, has existed almost since the beginning of time, according to a paper published in the journal Nature.

«About half of the largest galaxies the Universe has exhausted its stocks of «star materials» another 9 billion years ago. The reason for this was considered heavy duty flash of star formation caused by the collision of galaxies. Much to our surprise, these «dead» galaxies have a spiral and not an elliptical shape, which is contrary to this theory,» write Sune Toft (Sune Toft) from the Niels Bohr Institute in Copenhagen (Denmark) and his colleagues.

In the center of the milky Way and almost all its «cousins» there is a supermassive black hole, the invisible way «orchestrated» by the processes of circulation of matter throughout the galaxy. Long enough astronomers believe that the intensification of these black holes results in a gradual emptying of the galaxy and the cessation of star formation due to the fact that the black hole heats up and emits cold clouds of dust and hydrogen within galaxies.

These clouds of gas slowly cooling and gradually surround the galaxy in a giant cocoon of hot plasma, preventing the flow of cold gas flows from the intergalactic medium. As a result of these processes, scientists today believe that about half of the galaxies in the observable Universe is «living corpses» – they are not actually new stars are born. Other astronomers believe that the reason for the «death» of galaxies are their collisions among themselves, which lead to sudden outbursts of star formation and the «fading» of all stocks neutral gas.

Toft and his colleagues found that neither black holes, nor clashes with neighbors are not the cause of their death, received the first pictures of the oldest Central regions of galaxies that we see in the same condition in which they were 10.6 billion years ago.

These photographs scientists have received by studying one of the most small and inconspicuous galaxies of the young Universe, MACS2129−1, whose light was amplified by the gravity of a large cluster of galaxies MACS2129 located on the line between the Earth and MACS2129−1. To observe it, astronomers used the orbiting Observatory, the Hubble space telescope and XSHOOTER instrument mounted on the VLT ground-based telescope to obtain images of single galaxies.

The cycle of death

At first glance, she was no different from the typical «dead» elliptical galaxies that can be seen in the vicinity of the milky way – the stars in it is actually not formed, and she was painted in red tone, color, long-lived red dwarf stars and older stars, almost exhausted their reserves of thermonuclear «fuel».

On the other hand, when scientists began to study its spectrum, they noticed something unusual – it turned out that MACS2129−1 was not round but flat, similar to a typical «pancake» of the milky Way and other spiral galaxies.

This discovery was a real surprise for astronomers, since the possibility of damping of spiral galaxies in a young Universe had just not been considered. Scientists believed that «death by gluttony», as he calls this process of Russian-German astronomer Alexey Finogenov, typical for elliptical galaxies, resulting from the collision of two large galaxies of other types.

What could cause the galaxy to die? Scientists believe that her death could be involved dark matter, clusters which surround the outskirts of all galaxies. She could make «normal» matter flows which fall on MACS2129−1 of the intergalactic medium, to expedite their movement and to warm up, depriving the galaxy of access to the latest «star materials» and led to the complete cessation of star formation.

This idea is not quite consistent with modern concepts on the evolution of galaxies today astronomers believe that galaxies start to die from within, and not outside, as suggested by Toft and his colleagues. In addition, it is unclear how MACS2129−1 and its «cousins» has become a modern «dead» elliptical galaxies. Scientists plan to find the answer to both of these questions by watching other ancient galaxies in search of analogues MACS2129−1.


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