Intermediate black holes would be created by black holes swallowing thousands of stars

The first candidates to stellar black hole they were discovered in the early 1970s with the rise of X-ray astronomy in particular. But we can say that the first candidates for the title of black hole tout court were discovered in the early 60’s with the quasars. During the following years from the end of the XXi century, it is increasingly likely that black holes prominent stars had masses between 5 and 15 solar masses while the supermassive black holes in the heart of large galaxies, such as Milky Wayit contained one million to several billion solar masses.

If the birth of stellar black holes is not very mysterious, for collapse gravity of a star at the end of its life, which probably initially contains more than 30 solar masses, that of supermassive black holes is still enigmatic although several plausible scenarios have been proposed. This implies the existence of black holes of medium mass between the two populations that could fuse during the collision of galaxies and also accumulate subject matter of currents ofhydrogen falling on galaxies or by swallowing stars.

This last hypothesis is not without its problems because it is well known that in galaxies, the distances between stars are such that they can be considered to form a gas no collisions. However, today an article published in Astrophysics Journal by a team ofastrophysicists and which can be read freely in arXiv it allows us to reconsider this scenario from another perspective that makes it much more interesting and credible.

For about a decade, there are indications of the existence of intermediate black holes and what now seems promising to explain at least part of this existence is that in a significant fraction of large galaxies we find clusters of nuclear stars. Those clusters of nuclear stars (NSC), as we say in English, are at the center of most spiral galaxies and are denser (in 106 at 108 star-shaped solar masses in a region of about tenlight years of radius) than the globular clusters and the open clusters of stars while containing old stars, as the first, and young stars, as the second.

Catalysts of stellar encounter

NSCs are found mainly in galaxies that are not too massive, such as the Milky Way, and generally in those where the lightest supermassive black holes are observed, if they do not. Our galaxy has NSC and its central giant black hole it contains only about 4 million solar masses.

Observations made in the area of X-rays with the telescopes space Chandra and in the visible with the telescope Hubble highlighted in more than 100 NSC galaxies containing particular black holes in a sample of 29 that emerged from data studies collected by the two instruments together.

They seem to confirm a theory of growth in allau stellar black holes in these clusters whose density allows the stars to approach these black holes to the point of being destroyed by tidal forces, giving rise to the famous Tidal interruption events (or TDE) which can be translated into French as “tidal rupture events”, modeled during the 1980s by Jean Pierre Luminet and Brandon Carter.

In an NSC, according to the researchers’ calculations, a star hole born in the center will destroy and swallow the matter of thousands of stars, thus transforming into a black hole of intermediate mass towards the center of the galaxies. Calculations also show that there is a density threshold, and that it also depends on the speed in which the stars of the clusters move, from which the process of growth that consumes stars really begins.

As the theory predicts, NSCs above the calculated threshold contain more growing black holes, which supports the theory. The process of uncontrolled growth can occur in any sufficiently dense cluster and therefore still todayUniverse and not at the beginning of its history. Which is another verifiable prediction.

A brief presentation of the discovery made about the possible origin of the intermediate black holes. For a fairly accurate French translation, click on the white rectangle at the bottom right. English subtitles should then appear. Then click the female to the right of the rectangle, then “Subtitles” and finally “Automatically translate.” Choose “French”. © Chandra X-ray Observatory

Are you interested in what you just read?

Leave a Comment