Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ “Supermassive mutant” – leads to the “Cambrian explosion” of star formation

“Supermassive mutant” – leads to the “Cambrian explosion” of star formation

“Black holes are the seductive dragons of the universe,”

; writes science fiction author Robert Cover, “outwardly quiet but violent at heart, mysterious, hostile, original, radiating a negative radiance that draws everyone to them, engulfing all who come too close.” … those strange galactic monsters for whom creation is destruction, life to death, order of chaos. “

But sometimes in cosmic evolution, as in terrestrial evolution, a freak, a calm mutant, appears. In a stellar cluster without an active supermassive black hole in the cluster’s central galaxy, actively pumping energy into its surroundings, the gas can cool enough to produce a huge rate of star formation – a “Cambrian explosion” of creation. stars – according to Carter Rhea, at the University of Montreal about what can happen when a giant black hole does not interfere in the life of a galactic cluster. “This kind of black hole closure can be a crucial way to form stars in the early universe.”

The largest structures in the universe

Galactic clusters are the largest structures in the universe held together by gravity. They are made up of three main features: hundreds or thousands of individual galaxies, unseen dark matter, and a huge amount of hot gas that emits X-rays.

Astronomers using NASA’s Chandra X-ray Observatory and other telescopes have shown that the passive behavior of a black hole in the galactic cluster SpARCS104922.6 + 564032.5 (short for SpARCS1049), 9.9 billion light-years from Earth, leads to a large current. from star formation.

“Supermassive valve” – ​​emitting hot, X-ray gas

Galactic clusters contain hundreds or thousands of galaxies penetrated by hot X-ray emitting gas that exceeds the combined mass of all galaxies. Ejections of material fed by a supermassive black hole in the central galaxy of the cluster usually prevent this hot gas from cooling to form a huge number of stars. This heating allows supermassive black holes to influence or control the activity and evolution of their host cluster.

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900 new suns a year

Based on observations from the Hubble Space Telescope and the Spitzer Space Telescope, astronomers have previously discovered stars that form at an extraordinary rate of about 900 new suns a year in SpARCS1049. This is over 300 times faster than the speed at which our Milky Way galaxy forms its stars at a walking speed of 3 solar masses per year. (At the speed observed in SpARCS1049, all the stars in the Milky Way can only form in 100 million years, which is a short period of time compared to the age of our Galaxy of more than ten billion years.)

“It reminds me of the old expression, ‘when the cat is away, the mice will play,'” said Julie Hlavacek-Larondo of the University of Montreal in Canada, who holds the Canadian Research Department of Black Hole Observational Astrophysics and leads the study. “Here the cat or the black hole is quiet and the mice or the stars are very busy.”

Cooling gas sparks star formation

Astronomers ask: what is causing this great cycle of star birth? The answer may come from new data from Chandra, revealing the behavior of the hot gas about 80,000 light-years from the center of SpARCS1049 in a region outside any of the galaxies in the cluster. In most of the cluster, the gas temperature is about 65 million degrees. At the star site, however, the gas is denser than average and has cooled to a temperature of only about 10 million degrees. The presence of this cooler gas suggests that other undiscovered gas tanks have cooled to even lower temperatures, allowing a huge number of stars to form.

Although there are many examples where the energy injected by black holes in the surrounding environment is responsible for reducing the rate of star formation by factors of tens or thousands or more, these clusters are usually only a few hundred million light-years from Earth. and are much older SpARCS1049.

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Missing signs of a supermassive black hole

In the case of SpARCS1049, astronomers saw no sign that a supermassive black hole in the central galaxy was actively pulling into matter. For example, there is no evidence of a jet of material blowing out of a black hole in radio waves, or of a source of X-rays from the middle of the galaxy showing that matter was heating up when it fell on a black hole.

“Many astronomers thought that without the intervention of a black hole, star formation would fall out of control,” said co-author Tracy Webb of McGill, who first discovered SpARCS1049 in 2015 with the Spitzer Space Telescope. “Now we have evidence to observe that this is indeed happening.”

Why is the black hole so quiet? The observed difference in position between the densest gas and the central galaxy may be the cause. This would mean that the supermassive black hole at the center of this galaxy is starving for fuel. The loss of fuel source for the black hole prevents bursts and allows the gas to cool smoothly, cooling the thickest gas the fastest. One explanation for this compensation is that two smaller galactic clusters collided at some point in the past to create SpARCS1049, displacing the densest gas from the central galaxy.

A paper describing these results was published in The Astrophysical Journal Letters.

The Daily Galaxy, Max Goldberg, through the Chandra X-ray Observatory and NASA

Image credit: X-ray: NASA / CXO / Univ. from Montreal / J. Hlavacek-Larrondo et al; Optical / IR: NASA / STScI

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