13.8 billion years ago, the Big Bang marked the birth of our universe. All substances were then in the form of mixtures of charged particles, protons, electrons and photons. It was only after 380,000 years that the first atom was constructed by recombination, the Universe expanded enough to allow normal cooling, which was less than 3000 Kelvin. Then follows the so-called “Dark Age” period, between 500 million years and one billion years after the Big Bang, during which all substances are electrically neutral. It then condenses to form first hydrogen, then helium, and heavier and heavier atoms, until newborn stars are formed. But their radiation, emitted in the ultraviolet, is directly absorbed by the surrounding hydrogen gas.
From the dark ages to rebirth
The end of the dark ages is marked by new ionization due to the formation of stars and galaxies. These then emit radiation, which is powerful enough to cross and ionize the hydrogen cloud. But the exact duration and detailed mechanisms of this change are not clear, as the absorption of radiation by hydrogen on the one hand makes any observation of this period difficult, on the other because the stars are already extinct at the beginning of the recombination, which further observes them. Complicates To overcome these obstacles, scientists are turning to alternative solutions: among them, the use of Concerro, a spectrometer installed on the Apex telescope in Chile to examine millimeter lengths corresponding to cold gas emitted by galaxies after refinement. Does.
Another solution involves observing galaxies that would be similar to primary galaxies: analysis of the radiation emitted from them may make it possible to understand the transition to reunion. Since 2016, a few dozen of these galaxies have been found, including the galaxy AUDFs01, which emit highly ultraviolet regions. They are small, compact galaxies with large numbers of rising or forming stars. A study conducted by researchers at the University of Geneva in 2016 also showed that one type of galaxy, in particular of the “pea” galaxies, would be partially responsible for the reunion.
Pox 186, a small galaxy not far away
Recently, astronomers at the Institute of Astrophysics at the University of Minnesota also made an interesting discovery, which could explain how these galaxies were able to release enough power to ionize a cloud of neutral hydrogen. Using the data from the Gemini Telescope, he observed the first galaxy in a “blow away” position, that is to say, a part of the hydrogen cloud around it has separated. This elimination of hydrogen is possible only by the very rapid release of power, which escapes the light. This state, considered possible by researchers since 2016, was never actually seen. According to scientists, it is caused by a number of supernovas, caused by these unique explosions of stars at the end of their lives, which occurred in no time.
The galaxy, named Pox 186, was initially discovered in 1981, and has similar characteristics to so-called “pea” galaxies: small enough to fit into the Milky Way, with researchers suspecting that its larger size combined with its Compact Size. The stars – which reach 100,000 solar masses – make this rejection of hydrogen possible. “The formation of stars can be thought ofBalloon inflation The study’s lead author, Nathan Aigen, recently received a master’s degree in astrophysics from the University of Minnesota. “If the swelling was too intense, there would be a rupture or a hole in the surface of the balloon that would allow some of the emitted energy to pass. In the case of this galaxy, the star formation was so energetic that the balloon. Tore up, and exploded. Gone. “
Research is far away
These results, published in The Astrophysical Journal, confirm that it is possible to eliminate a cloud of neutral hydrogen, leading to the supposition that primordial galaxies are responsible for being more reliable. “There are many scenarios in science where we control a situation, but we don’t believe it to be reality”, Add eggen. “So verifying that this type of event can occur is really important. If this scenario is possible, it means that there are other galaxies that have exhausted their hydrogen in the past. The consequences of this rejection are Understand. Gives direct clues. Similar conditions as effects occur during reunification.
Research continues to actively try to locate the reunion mark, The mission that Conciero should fulfill but also the James Webb Telescope, to be launched in October 2021.