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In this week's astronomical news: a gigantic superamas of galaxies are hiding in the primitive universe, while Fermi's telescope data alludes to two supermassive black holes locked in a gravitational dance.
A supercluster of colossal galaxies in the primitive universe
A proto-superamas of the galaxy dubbed Hyperion is the most massive structure known at a time and distance as far apart – about 2.7 billion years after the Big Bang. This visualization of Hyperion is based on real data.
L. Calçada (ESO) / O. Cucciati et al. 2018
The most massive structures in the universe are superclusters, complex networks of galaxies extending over hundreds of millions of light-years. Now researchers have identified what could be a gigantic predecessor of modern superclusters. The discovery could help astronomers better understand how these monsters appeared and evolved to become the cosmic beasts around us today.
The light of this proto-superamas takes about 11 billion years to reach Earth. Astronomers see it about 2.8 billion years after the Big Bang. The discoverers nicknamed it Hyperion, in reference to one of the Titans of Greek mythology. Seven clusters of galaxies, whose mass varies between 10,000 and 270,000 billion suns, seem linked by filaments of galaxies covering about 20 billion billion light-years cube. The set is about as massive as 4.6 quadrillions of suns.
Although it is not the first cluster of galaxies seen in the primitive universe, none is as massive or as vast as this one.
Olga Cucciati (National Institute of Astrophysics, Bologna, Italy) and her colleagues discovered the teenage supercluster in the data from the Ultra Deep VIMOS (Visible Multi-object Spectrum) study, aiming to obtain offsets to the red of about 10,000 weak galaxies using the very large telescope. Chile.
The results of the team will appear in Astronomy and astrophysics and can be found on the arXiv astronomy preprint.
Flickering gamma rays from a distant galaxy
A pair of supermassive black holes whipping one around the other could explain the recurring fluctuations of gamma rays from the heart of a distant galaxy.
In 2015, researchers working with NASA's Fermi gamma-ray space telescope detected allusions to periodic modulation of gamma rays emitted by a galaxy named PG 1553 + 113, located nearly 5 billion light years away. of the earth. Now, by analyzing Fermi data over 10 years, astronomers confirm that something varies the intensity of these gamma rays every 2.2 years. In addition, gamma-ray vacillation corresponds to similar changes observed in visible light, X-rays, and radio waves.
Stefano Ciprini (Italian Space Agency, Rome) and his colleagues announced their findings at a press conference on 17 October.
The researchers explain that all these radiation is probably generated by the hot gas that swirls around a pair of supermassive black holes. As the black holes revolve around each other, gamma-ray fountains precede, alternately pointing at us and leaning forward. The researchers warn however that this interpretation is only a possibility. However, if a pair of supermassive black holes live in this galaxy, it could be a good target for the European Space Agency's eLISA satellite, a gravitational wave detector scheduled for launch in 2034.
The luminosity of the gamma rays of the PG 1553 + 113 galaxy has a period of 2.2 years (in purple) which corresponds to the fluctuations of the visible light (in white).
S. Ciprini et al. 2018
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