Black hole fails to do its job

Credit: X-ray: NASA / CXO / Univ. Montreal / J.K. Helwacek-LaRondo et al; Optical / IR: NASA / STScI

Astronomers have discovered what can happen when a supermassive black hole does not interfere with the life of a galaxy cluster. Using NASA’s Lunar X-ray Observatory and other telescopes, they have shown that passive black hole behavior may explain a notable edge of star formation occurring in distant clusters of galaxies.

The galaxy clusters contain hundreds or thousands of galaxies that are distorted by hot, X-ray emitting gas, which affects the combined mass of all galaxies. Ejections of material driven by a supermassive black hole in the central galaxy of the cluster usually prevent this hot gas from cooling to form a large number of stars. This heating allows supermassive black holes to influence or control the activity and growth of their host clusters.

But what if that black hole ceases to be active? The galaxy cluster SparCS104922.6 + 564032.5 (abbreviated SpARCS1049) located 9.9 billion light years away from Earth is supplying an answer.

Based on observations received from NASA’s Hubble Space Telescope and the Spitzer Space Telescope, astronomers first discovered that the stars were formed at an extraordinary rate of about 900 new sun masses per year in sparse 101049. It is 300 times faster than the rate of our Milky Way, Milky Way, its stars are being formed. (At the rate seen in SpARCS1049, all the stars of the Milky Way can form in just 100 million years, which is a much shorter time than our galaxy is over ten billion years old.)

“It reminds me of the old expression ‘when the cat is away, the rat will play,” said Julie Havlésk-Larondo of the University of Montreal in Canada, who led the study. “The cat here, or the black hole, is quiet and the mice, or stars, are very busy.”

This fiery star formation is occurring outside the cluster of galaxies about 80,000 light-years from the center of Sparkus 1049 of any region. Astronomers have been asking: What is the reason for this eccentric cycle of star birth?

New lunar data revealing hot gas behavior in SpARCS1049 may provide the answer. In most clusters, the gas temperature is around 65 million degrees. However, the gas at the site of star formation is more dense than average and it cools to a temperature of about 10 million degrees. The presence of this cooler gas suggests that other undeclared gas reservoirs have also cooled to low temperatures capable of forming large numbers of wires.

University of Montreal co-author Carter Rhea said, “Without a black hole to actively pump energy into its surroundings, the gas can cool sufficiently, so it can have an impressive rate of star formation.” “This type of black hole closure can be an important way for stars in the early universe.”

While there are many instances where energy is injected into the regions around them to reduce the rate of star formation by factors of tens or thousands or more, these clusters are typically only a few hundred million light years from Earth and SparCS1049 is older than this.

In the case of SpARCS1049, astronomers see no indication that a supermassive black hole in the central galaxy is actively pulling into the case. For example, there is no evidence for a jet of material moving away from the black hole on the radio wavelength, or an X-ray source from the middle of the galaxy indicating that the black hole had fallen.

McGill co-author Tracy Webb said, “Many astronomers have thought that the creation of stars would go out of control without the interference of a black hole, which first discovered SpARCS1049 in 2015 with NASA’s Spitzer Space Telescope.” “Now we have observational evidence as to what it really is.”

Why is a black hole so cool? The observed difference in position between the condensed gas and the central galaxy may be due to this. This would mean that the supermassive black hole in the center of this galaxy is being starved for fuel. The loss of a fuel source to the black hole prevents outbreaks and allows the gas to cool without interruption, with the fastest gas being cooled. One explanation for this offset is that two small galaxy clusters collided at some time to form SpARCS1049, which was moving the dense gas away from the central gas.

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

The largest starvation of the largest scale black hole in the universe

more information:
Evidence of fugitive gas cooling in the absence of supermassive black hole feedback in the era of cluster formation: arXiv: 19.15660 [astro-ph.GA]

Provided by Chandra X-ray Center

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