Identify some of the oldest stars in the universe

Carlos Frenk Mora graduated from the Faculty of Science, led a study that revealed satellite systems as a new resource to understand "the primitive universe"

It is the astronomical equivalent to find the remains of the first people to inhabit the earth, said Frenk Mora, one of the foremost Mexican astronomers.

With over 13 billion years, the satellite systems Segue-1, Bootes I, Tucana II and Ursa Major I are one of the oldest in the universe

Some of the weakest satellite systems that revolve around the Milky Way are the first to form in our Universe, revealed the astrophysicist Carlos Frenk Mora, graduated from the Faculty of Sciences of UNAM and in 2017 was recognized as Commander of the Order of the Empire British .

"Finding some of the first galaxies formed in our universe in orbit in the backyard of the Milky Way is the astronomical equivalent of finding the remains of the first people who populated the earth, and it's very exciting," said the university scientist in the article in the United States The imprint of cosmic re-ionization on the brightness function of galaxies, published by the magazine The Astrophysical Journal.

These ancestral galaxies are: Segue-1, Bootes I, Tucana II and Ursa Major I, with more than 13 billion years. "What we did was to collect all the data and interpret them within the schedule we have about the evolution of the universe," explained Frenk Mora.

The research also included Alis Deason, from the Computational Cosmology Institute at the University of Durham, England, and Sownak Bose, from the Harvard-Smithsonian Center for Astrophysics, USA.

"The finding supports the current model for the evolution of our universe, the so-called" dark-cold matter lambda ", in which the elementary particles that make up dark matter stimulate cosmic evolution," added the Mexican specialist.

Using instruments such as the VTL, from the European Southern Observatory, satellite systems that are held by larger gravitational forces near larger ones (such as Andromeda or the Milky Way) are studied more thoroughly.

With computer modeling systems, Frenk Mora and his team identified two populations of satellite systems around our galactic neighborhood.

The first contains galaxies formed during the dark cosmic era. The second, with brighter objects that formed hundreds of millions of years later, once the hydrogen ionized by the intense ultraviolet rays emitted by the first stars, could cool in more massive halos of dark matter.

Surprisingly, the team discovered that a theoretical model of galaxy formation that they had previously developed coincided perfectly with the data, allowing them to derive the formation times of satellite systems.

A decade ago, the weakest galaxies near the Milky Way would have been thrown out of the study, but with the new scientific equipment they have been revealed as "a new treasure to learn from the primitive universe," the specialist added.

Universal history

It is believed that when the universe was about 400,000 years ago, the first atoms were formed. These were hydrogen (the simplest element in the periodic table), they piled up in the clouds, but gradually cooled down to settle in the "halos" of dark matter that were removed from the Big Bang.

This phase is known as "the cosmic dark time", which lasted about 100 million years. In the end, the gas that had cooled down in the halos had started to become unstable, forming stars and thus the first galaxies that gave way to light.

The intense ultraviolet radiation of the first galaxies destroyed the remaining hydrogen atoms by ionizing them (killing their electrons), making it difficult to cool this gas and form new stars.

The process of galaxy formation stopped completely for the next billion years or so.

Eventually, the halo's dark matter became so massive that even the ionized gas could cool. The Milky Way formation was resumed, culminating in spectacular bright galaxies such as our galactic neighborhood: the Milky Way, explained Carlos Frenk, one of the astronomers graduated from UNAM who is recognized the world over for his theory of dark matter for the formation of galaxies.

With information from the UNAM

Source link

Leave a Reply