Is there another supermassive black hole at the center of our galaxy?

Is there another supermassive black hole at the center of our galaxy?

TelescopeTelescope Hubble has shown us that there are many cases on a large scale GalaxiesGalaxies bumping intouniverseuniverse observable, and has been for billions of years.

However, after the discovery of quasars almost 60 years ago, we immediately began to think that black holesblack holes Huge masses may be hidden in the hearts of galaxies. Thus, since 1964, the great astronomyastronomy Zeldovich, Novikov and Salpeter proposed that KaiserKaiser more precisely, more generally active galactic nucleusactive galactic nucleusHappen supermassive black holesupermassive black hole growing from CaseCase, In 1971, Donald Lyndon-Bell and Martin Rees proposed on their part that at the center was a GalaxyGalaxy And in general many others. Since at least the early 1990s, it seems clear that most large galaxies harbor at their center one of these estraceestrace compact.

This numerical simulation brings astrophysicists a step closer to understanding the type of light signals produced when two supermassive black holes surrounded by matter, millions to billions of times the mass of the Sun, head towards a collision. This simulation fully incorporates the physical effects of Einstein’s theory of general relativity and shows that the gas in such systems would glow mainly in ultraviolet light and X-rays. For a fairly accurate French translation, click on the white rectangle at the bottom right. Then the English subtitles should appear. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Translate automatically”. Select “French”. NASA’s Goddard Space Flight Center

binary black hole formed from galaxy merger

Since then, one can imagine that during a post-collision collision between two massive galaxies, a supermassive binary black hole may form, the two original black holes present in the two initial galaxies being propelled by some process towards the heart. have been of new galaxy. As a bonus, both of these black holes were also supposed to start producing copious amounts. gravitational wavesgravitational waves and finally, becauseenergyenergy Colliding with these waves, it gets destroyed.

It is suspected that these are the same waves that have been detected over the years by members ofInternational Pulsar Time Table (IPTA). So one can naturally ask the question of the existence of a supermassive binary black hole at the center of the Milky Way.

Some answers have been provided on this topic so far. Via an article on arXiv by a team of researchers including Nobel laureate in physics Andrea Ghez, who helped establish the existence of the black hole behind the radio source Sagittarius A* at the center of our galaxy, physicistphysicist American Clifford Will, one of the great masters of various observation tests general relativitygeneral relativityand Aurélien Heiss, working at the Paris Observatory and who is also working on testing the theory GravityGravity extension of the principle ofEinsteinEinstein And especially with the central black hole of the Milky Way.

Andrea Ghez, professor of physics and astronomy at UCLA in California, tells us about her work on the supermassive black hole at the center of the Milky Way, for which she won the Nobel Prize in Physics. To get a fairly accurate French translation, click on the white rectangle at the bottom right. Then the English subtitles should appear. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Translate automatically”. Select “French”.

Let’s clear things up a bit. A supermassive black hole has at least one million solar masses and it is believed that stellar black holes with a maximum of a few tens of stellar masses can form. collapsecollapse GravitationalStarsStars On Large scale. We can see the mass climbing of merging stellar black holes, but we know that there are also so-called black holes with masses intermediate between stellar black holes and supermassive black holes.

We also know of some cases of binary supermassive black holes in galaxies from observations.

Orbiting stars betray massive black holes

It should also be remembered that Reinhard Genzel and Andrea Ghez received the 2020 Nobel Prize in Physics for nearly two decades of studying the movements of stars in the center of the Milky Way around the region containing the radio source Sagittarius A*.

The particularly fast motion of these stars, such as those called S0-2, or S2, showed that there was a mass of more than 4 million solar masses, which was barely radiating and in a VolumeVolume So weak that the most rational explanation was in fact that it was a black hole described by the theory of general relativity to a first approximation.

Eventually it was discovered that the movements of these stars could serve as a remarkable laboratory for testing new physics, such as the existence of a fifth force.

A video on observing stars around supermassive black holes of the Milky Way with the VLT. Real images are mixed with artificial images. © ESO

Finally, the presence of a second supermassive black hole To revolve aroundTo revolve around Light around Sagittarius A* may have already been shed many years ago. The article published today, which also uses relativistic movements of stars around black holes, was also illustrated by members of the collaboration event horizon telescope, porteporte So actually on the presence of a black hole of intermediate mass in orbit around Sagittarius A*.

To be precise, astrophysicists have come to the conclusion that between 1,000 UAUA (about the orbital radius of S2, the closest known supermassive black hole) and 4,000 AU away from Sagittarius A*, there may not be an intermediate black hole with a mass between 1,000 and 100,000 solar masses.

If a black hole of intermediate mass exists and is closer to Sagittarius A* than S2, its mass cannot exceed 400 times SoleilSoleil,

What is the history of gravity? What is the quantum theory of gravity? Why search for alternative theories of gravity? What tools can be developed to evaluate these new theories? During a presentation at ENS, Aurélien Heiss reviewed the various tests of general relativity that have been done before and gave an overview of future tests to be done. © Ecole Normale Supérieure – PSL