Astronomers have specified the time of the end of the era of “cosmic dawn”

(ORDO NEWS) — Observations of 67 ancient quasars allowed astronomers to determine the end time of the process of reionization of neutral intergalactic hydrogen gas formed as a result of the Big Bang.

It turned out that it lasted about 200 million longer than previously thought, and ended 1.1 billion years after the birth of the universe. The results of the study are presented in the journal Monthly Notices of the Royal Astronomical Society.

“We now have the strongest evidence that the reionization process ended much later, in a space age that is easier to observe with the instruments available to us today.

And, although the adjustment may seem insignificant, given the billions of years since the Big Bang, in fact, this additional time is enough to produce several dozen stellar generations in early cosmic evolution, ”says Frederick Davies, co-author of the study from the Institute of Astronomy. Max Planck (Germany).

Astronomers have specified the time of the end of the era of cosmic dawn 2
Schematic representation of space history. Observation of the first quasars provided information about the era of “reionization” that followed the “dark ages” and preceded the “age of matter” that continues today

From its beginning to its current state, the universe has gone through various phases. During the first 380 thousand years after the Big Bang, it was filled with hot and dense ionized plasma.

After this period, the Universe has cooled down enough for protons and electrons to begin to combine into neutral hydrogen atoms. For the most part, during these “dark ages” there were no sources of visible light.

About 100 million years later, the first stars and galaxies began to form, whose ultraviolet radiation subsequently ionized the gas filling the Universe again.

This era is known as “cosmic dawn”. Today, all hydrogen distributed between galaxies is completely ionized, however, when this process was completed, a widely discussed topic of recent years.

“Light from quasars passes through many hydrogen clouds on its way to Earth, each leaving its own imprint. High-resolution source spectrum properties and modeling suggest that the 1.1 billion year age of the universe is the latest time that neutral hydrogen gas was present in intergalactic space and influenced the light of these ancient quasars,” said Sarah Bosman, lead author of the study from Institute of Astronomy. Max Planck.


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