Do giant black holes have a limit? Discovery of the most monstrous of them

At the centers of galaxies reside gravity ogres called supermassive black holes. That of the Milky Way is, for example, 4 million solar masses, a small one in this category. A little further from us, 54 million light years away and in a much larger galaxy than ours is M87*, the very first black hole that we have managed to image and which “weighs” 6 billions of solar masses!

Some astronomers consider that from 10 billion, it is another category of black hole, called ultramassive. We know a fairly large list. Thus, Tontantzilla 618, better known by his nickname Tone 618is the most gigantic black hole whose mass has been measured, a whopping 66 billion times our Sun! Its radius has been measured at 190 billion kilometers, more than 40 times the Sun/Neptune distance.

But there is perhaps even more monstrous. According to one estimate, Phoenix A could reach 100 billion solar masses.

Do these ultramassive black holes have no limits? It seems so!

The work of Priyamvada Natarajan (Yale University) and Ezequiel Treister (ESO) shows that this obesity is not infinite. Based on the link found between the luminosity of the central bulge of a galaxy and the mass of its supermassive black hole – or ultramassive in this case – these scientists deduced that a mechanism regulates growth (see graph at the end of the article).

And that’s good, because the James Webb space telescope discovered recently a black hole whose growth is so accelerated that it exceeds a theoretical luminosity limit by 40%. It may seem strange to you that a black hole is identified by its brightness, but in reality it is the dust and matter that revolves around it, radiating. This is the famous accretion disk, its meal in a way, as imagined in the film Interstellar.

The most voracious supermassive or ultramassive black holes are generally quasars, identifiable in the cosmos by the extreme luminosity emanating from them. This is the case of Ton 618, for example. These quasars generally have a particularity: a so-called “astrophysical” jet which takes root in the accretion disk and escapes going up along the black hole. Be careful, nothing obviously comes out of the latter, it is matter which never entered it and was as if pushed back. Here is the magnificent astrophysical jet produced by M87 A* photographed by Hubble.

Astrophysical jets disrupt black hole growth

However, this famous jet would participate in the self-regulation of super and ultramassive black holes. “In agreement with the theoretical arguments we have put forward, supermassive black holes disrupt their own growth”explains Priyamvada Natarajan.

By effect cool kissthis heated gas can no longer be used for star formation, because gravity requires excessively cold gas to cause collapse in one direction. These galaxies will therefore produce fewer stars little by little, as recent observations seem to confirm, for example the Pablo galaxy that we presented a few weeks ago.

In summary, the list of the largest black holes known to astrophysicists could still grow, but perhaps we will never find specimens crossing the limit of 100 billion solar masses. A thousand billion thousand ports!