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Vast oceans of mysterious dark matter found in huge primordial galaxies



Our most powerful telescopes have searched the depths of the most massive galaxies to find vast oceans of mysterious dark matter.

Using the world's largest radio telescope – Atacama Large Millimeter / submillimeter Array (ALMA) in Chile – a team of researchers has discovered evidence that massive galaxies not only form incredibly rapidly, but are brimming with mysterious dark matter.

In an article published in Nature researchers at the University of Arizona revealed how ALMA surprised the team to find examples of massive star-filled galaxies seen when the cosmos was less than a billion years old.

Suggesting that small galactic building blocks could assemble quickly, this discovery was against the common conviction that the first galaxies formed after the Big Bang would share many similarities with some of the dwarf galaxies we see today in the near universe.

Only then, it was thought, these first ks blocks would be incorporated into larger galaxies over a few billion years.

The two galaxies observed by ALMA were spectacular, the team said, since they were seen when the universe was only 780m old and these cosmic monsters are locked in an even more massive cosmic structure, a halo of dark matter several billion of times more massive than the sun.

"With these exquisite observations from ALMA, astronomers are seeing the most massive galaxy known in the first billion years of the universe in the process of assembling itself," said Dan Marrone, lead author of the article.

  ALMA galaxy shooting

A composite image showing ALMA data (red) of the two SPT0311-58 galaxies. These galaxies are displayed on a background of the Hubble Space Telescope (blue and green). Image: ALMA (ESO / NAOJ / NRAO), Marrone, et al .; B. Saxton (NRAO / AUI / NSF); NASA / ESA Hubble

& # 39; Large amount & # 39; of cosmic dust

This assembly period occurred during a time in the cosmic history known as the "reionization epoch", when most of the intergalactic space was impregnated with a cold haze that obscured hydrogen gas .

When more stars and galaxies formed, their combined energy ionized the hydrogen between the galaxies resulting in the universe we see around us today.

Using some sophisticated computer models to eliminate the astrophysical phenomenon of the gravitational lens, the team could see that the larger of the two galaxies is forming stars at a rate of 2,900 solar masses per year.

In addition to that, it also contains about 270 billion times the mass of our sun in gas and almost 3 thousand times the mass of our sun in the dust, a "huge huge amount," according to the team.

The observations also allowed the researchers to get a better view of the elusive and mysterious halo of dark matter surrounding the bot h galaxies, but fortunately our ability to measure it is not so unknown.

Chris Hayward, one of those involved in the research, said: "Fortunately, we know very well the relationship between dark matter and normal matter in the universe, so we can estimate what the mass of matter halo should be dark. "


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