The James-Webb would overturn the theory of the co-formation of supermassive black holes and galaxies – MSteka

The James-Webb would overturn the theory of the co-formation of supermassive black holes and galaxies

The collaboration Event Horizon Telescope has provided us for several years with images and measurements concerning radio sources M87*M87* in the galaxy Messier 87Messier 87 And Sgr A*Sgr A* in the Milky Way. They very convincingly support the theory that these sources are in fact rotating supermassive black holes accreting matter. M87* thus has an estimated mass of 6.5 billion solar masses and Sgr A* at 4.3 million solar masses. When a lot of matter is accreted, the black hole becomes a quasar, a star shining on its own like a large entire galaxy and which emits powerful jets of matter, as explained in the video below.

We also know that there are many supermassive black holessupermassive black holes in the cosmoscosmos observable and that the vast majority of large galaxies have contained one for billions of years. Furthermore, there is a relationship between the mass of galaxies and the mass of the black holes they contain which very strongly suggests that the two grow together and coevolve.

However, we do not know very well how these giant black holes were born or what their exact relationships with galaxies are, even if certain scenarios are more credible than others in the debates on these subjects in the scientific community. We hoped that the James-Webb would help us to see things more clearly and in fact, it brought new elements for reflection – according to an article published in Astrophysical Journal Letters and freely accessible on arXiv.


Jean-Pierre Luminet, research director at the CNRS, and Françoise Combes, professor at the Collège de France, tell us about black holes, in particular the large supermassive black holes in galaxies which are behind quasars and which impact the evolution of galaxies. © Hugot Foundation of the Collège de France

Black holes, the seeds of galaxy formation?

The article mentions among the researchers involved one of the big names in cosmology and the Big Bang theory, Joseph Silk, professor at the Department of physicalphysical and astronomy at Johns Hopkins University (United States) and at the Institute ofastrophysicsastrophysics of Paris, Sorbonne University.

In a press release from Johns Hopkins University, he comments on the publication of which he is the main author: “ We know that monstrous black holes exist at the centers of galaxies near our Milky Way, but the big surprise now is that they were also present at the beginning of theUniverseUniverse and were almost like building blocks or seeds for the first galaxies. They really stimulated everything, like gigantic training amplifiers ofstarsstarswhich represents a complete reversal of what we previously thought possible, so much so that it could completely upend our understanding of galaxy formation. »

To arrive at these statements, Silk and his colleagues relied on the discovery made by the James-Webb a few hundred million years after the Bib Bang of a large population of small galaxies still not very massive but abnormally bright and reddened by the presence of dust, which indicates a very high rate of star formation and an abnormally rapid production of stars. This population of red and ultra-compact galaxies has been called the population of “ little red dots ”, which can be translated as “ little red dots “.

But that’s not all, these galaxies are also abnormally luminous because they present signatures of active galactic nuclei and therefore of giant black holes accreting matter already numerous early in the history of the cosmos observable in these nuclei of galaxies.

THE modelingmodeling of the beginnings of galaxy formation and the most commonly considered model for the formation of supermassive black holes do not fit well with these observations, which strongly suggests that they need to be revisited.

Standard scenarios based on black matterblack matter cold and thedark energydark energy cause the formation of galaxies to begin with vast cloudsclouds of gasgas which will collapse gravitationally giving embryosembryos of galaxies with the first stars. These embryos will continue to grow and form stars by accreting gas.

The first stars could not form like newer stars because there was no dust then and they had to be more massive than those we observe today. Several models exist giving rise at some point in the early evolution of galaxies to supermassive stars at their hearts, which when exploding will also give rise to giant but not yet supermassive black holes.

Primordial black holes or early supermassive stars?

But according to Silk and his colleagues, that’s not really how things would have happened. In fact, giant black holes would have been born, or were already there, with the embryos of galaxies and for hundreds of millions of years, jets and broadcastsbroadcasts of matter associated with theaccretionaccretion on these black holes would have compressed the gas in the overdensities of matter transforming into embryos of galaxies, then into dwarf galaxiesdwarf galaxies to the point of strongly catalyzing the formation of stars following thecollapsecollapse of clouds compressed by emissions from black holes and therefore the growth of galaxies.

Supermassive black holes would therefore have had a very important role in the very birth of galaxies. But according to researchers, about a billion years after the big Bangbig Bang, the activity of supermassive black holes began to sometimes produce the opposite effect. That is to say that their emissions of matter and radiation could on the contrary expel the gas contained in galaxies and therefore stop the formation of stars, unless these galaxies were then supplied with matter again, for example as in the theory of cold filaments of dark matter.

Still, while the idea that giant black holes existed much earlier than standard cosmological scenarios assume, we still don’t really know how they formed. The scenario of supermassive stars is still possible but they would therefore have appeared earlier than we thought. There is always also the possibility of the sea serpent of primordial black holes formed during the Big Bang even though the densities of matter and energy were very high and a whole spectrumspectrum density fluctuations could give rise to black holes of the mass of a mountain for example or already of several thousand solar masses.

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