[ad_1]
New research has focused on the abundance of primordial black holes that formed a few fractions of a second after the Big Bang and are 50 times more massive than the sun, thus analyzing the interaction of the light emitted by these extremely distant quasars with the Web network of filaments composed of gas and dark matter present in the universe.
"Black holes primitive (PBH) remain hypothetical objects for the moment," following direct observations of gravitational waves by detectors VIRGO and LIGO in 2016, explains Alvise Raccanelli of CERN. "Originally proposed by Stephen Hawking in 1971, they have come to the fore in recent years as possible candidates for dark matter. Dark matter is thought to account for about 80% of all matter in the universe. Explaining the least result would therefore be a major feat. Looking for evidence of the existence of PBHs, or excluding their existence, provides us with information about the physics of the primordial universe. "
"Eliminated" – Stephen Hawking's theory: Big-bang black holes, source of dark matter
Within the dense web of the cosmic network, scientists have focused on the so-called Lyman-alpha forest, the interactions of photons with hydrogen cosmic filaments, which reveal features closely related to the fundamental nature of the black matter.
Dark Matter – "Maybe Eon Particles Before the Big Bang"
"There is this whole structure in the far universe that has never been seen before. Sometimes I feel like an adventurer cartographer of the Middle Ages! Says Anže Slosar, a physicist at the Brookhaven National Laboratory, who was not part of the Lyman-alpha forest research.
"The loophole" – the discovery that could have predicted the reason for the existence of the universe
The image below of the simulation EAGLE, a simulation of the universe, shows the context of the formation of a single galaxy in the large-scale cosmic network. A recent study suggests that the first galaxies could form from a cold gas that accumulates from the cosmic network. (The Virgo Consortium, Schaye et al.)
The quasars (PKS 2349 at the top of the page is 1.5 billion light years from Earth) are the brightest objects in the universe. They provide a backlight to illuminate the intermediate hydrogen gas that fills the universe between us and them. We can see their shadows, and details in their shadows – in particular, the absorption characteristics in their spectrum known as the Lyman-alpha forest. What is amazing is that it allows us to see the universe so far.
"Deciphering the Enigma" – New Theories on Dark Matter
"We tested a scenario in which dark matter is composed of non-stellar black holes, formed in the primordial universe," says Riccardo Murgia, lead author of the recently published study in Physical Review Letters.
The research was conducted in collaboration with colleagues Giulio Scelfo and Matteo Viel from SISSA – International School of Advanced Studies and INFN – Istituto Nazionale di Fisica Nucleare (Trieste Division) and Alvise Raccanelli from CERN.
Simulations with SISSA's supercomputer Ulysses and ICTP have enabled the interactions between photons and hydrogen to be reproduced. The models were compared to the actual interactions detected by the Keck telescope in Hawaii. The researchers were then able to trace several properties of primordial black holes to understand the effects of their presence.
"We used a computer to simulate the distribution of neutral hydrogen at subgalactic scales, which manifests itself in the form of absorption lines in the far-distant spectrum," explains Murgia. "By comparing the results of our simulations with the observed data, it is possible to establish limits on the mass and abundance of primordial black holes and to determine if and to what extent these candidates constitute matter. black."
Secret of Dark Matter – "Huge Particles of the Planet or the Planet"
The results of the study seem to disadvantage the case where all dark matter is composed of some type of primordial black hole (those whose mass is greater than 50 times that of the sun) but exclude not totally that they can constitute a fraction. of that.
"We have developed a new way to easily and efficiently explore alternative scenarios of the standard cosmological model, according to which the dark matter is rather composed of massive particles in weak interaction (WIMP)".
These results, important for the construction of new theoretical models and for the development of new hypotheses on the nature of dark matter, offer much more precise indications to trace the complex path to understand one of the persistent mysteries of the cosmos. .
The Daily Galaxy via the International School of Advanced Studies (SISSA)
[ad_2]
Source link