We saw some “missing” things in the universe

AFP, Released Friday, September 17, 2021 at 4:21 p.m.

According to a study released Thursday, scientists have for the first time mapped a galaxy’s wind, a galaxy’s gas reservoir.

Astronomer Nicholas Pocho points out that “galaxies are dormant islands of stars”, but that dynamic structures, its formation and evolution are difficult to study.

Theoretically, galaxies formed atoms and molecules on top of a mysterious dark object, of unknown nature and therefore invisible, and about 16% of baryonic matter. ‘The visible universe.

As if that weren’t enough, observing galaxies reveals only 20% of this baryonic object. The rest – the “missing” thing – will be sent into space by the galaxy.

An international team led by researchers at the Lyon Astronomical Research Center (KRAL) mapped the Nebula of Missing Things using the Muse Spectrograph, in conjunction with the European Southern Laboratory’s Largest Telescope (VLT) installed in the Chilean desert of Atacama.

– An object reservoir –

“It’s like we’ve seen a glacier for the first time,” says Nicholas Boch, Crawlin’s researcher and co – author of the study, published in the prestigious British journal MNRAS.

Researchers have already observed nebulae in galaxies, but are still spreading. This time, Gal1’s observation of a young galaxy about a billion years old revealed that “the gas cloud produced by the galaxy’s air escapes on both sides of the galaxy’s disk, two asymmetrical cones.”

On a massive scale, this fixed cloud extends 80,000 light-years from the center of Gal1. In comparison, the diameter of our Milky Way is about 100,000 light-years.

Despite its size, the gas nebula only reflects “10 to 20% of the galaxy’s mass.” Posey mentions. It acts as a reservoir of matter, from which the galaxy stimulates its stellar formation.

Part of the cloud will fall back into the galaxy and form these stars, some of which will eventually explode, sending the object back to the nebula, and so on.

– Map “-

Scientists were able to establish a “map” of this nebula, providing information about its size and mass, thanks to happy conditions and a remarkable Muse tool.

The wide-field spectrograph presents a three-dimensional image that includes the analysis of light into two dimensions of optics, making it possible to detect the presence of primordial elements.

In this case a quasar – a bright object in the universe in particular – near the galaxy Gal1, as a “lighthouse”, betrays the presence of magnesium. “We found a similar element in the galaxy, so we found the gas associated with it,” he said. Observation of the two gas cones is possible, moreover, only because the galaxy view is presented in almost profile.

Astronomers already knew about this type of nebula in the universe closest to us, so recently, a CNRS press release mentions. But only one could have guessed their existence for the galaxies, still formed, like Cal 1, the universe, still far away, captured seven billion years ago, i.e. half its current age.

Researchers will now look at several galaxies to understand why “Gale1 has a cloud, why others do not, and what conditions are favorable for its existence.”

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