There are supermassive black holes in the heart of all massive galaxies. And they shred the stars that pass too close to them. But in this galaxy located at 600 million light years from our land, a second supermassive black hole is at work. This is the first time that astronomers witness such a situation.
THE astronomers Define supermassive black holes like those whose mass is greater than a million times that of our sun. And the researchers have already surprised many stars to shred stars before swallowing them up, about a hundred since 2018, thanks to the Zwicky Transienty (ZTF) installed on an observatory instrument Palomar (United STATES). It was intended to detect the explosions of supernovae. But it was also sensitive to other flashes bright. Like those issued by the spaghettification of a star. Spaghettification is the term we use to describe what astronomers more seriously qualify as a break -up event by tidal effect – or tidal Event disruption (TDE). The moment when the intense severity From a black hole literally tears the envelope of a star.
To fully understand the importance of the discovery in question today, it is useful to recall that the Supermassive black holes generally hide in the heart of galaxies They too massive. “It is therefore at the heart of these galaxies that we usually look for these tidal effects”explains Yuhan Yao, researcher at the University of California in Berkeley (United States), in a statement. But this is not that a luminous flash attracted the attention of his team. “We discovered a TDE – called AT2024TVD and which betrayed a black hole of a little over a million times the mass of our sun – About 2,600 light years from the center of the galaxy, which hides itself another supermassive black hole of around 100 million solar masses. It is the first of the kind discovery kind. »»
A collision between supermassive black holes in sight?
In Astrophysical Journal Lettersthe researchers therefore describe a system not quite like the others – even if two similar have already been detected in the past by X -ray satellites. Without the discovery is really a surprise. Because astronomers know that galaxies often collide. Each bringing their own black hole to the greater galaxy which forms during the fusion. At least until the two supermassive black holes collide themselves to form only one even more immense. The researchers have already identified large galaxies with supermassive black holes weighing several hundred billions of solar masses!
If the supermassive black hole that researchers from the University of California have just discovered come close to that located in the heart of its galaxy, the two will undoubtedly end up. But not for billions of years. THE gravitational waves that the event would not fail to issue are exactly those which should be able to be observed by the future mission Laser Interferometer space Antenna (Lisa). It will be launched by theEuropean Space Agency (ESA) during the 2030s. His goal, precisely: to study the black holes of several million solar masses.
Identify other wandering supermassive black holes
However, as the study of images returned by the Hubble space telescope shows no sign of merger between galaxies in the region, astronomers envisage other hypotheses to explain the presence of this supermassive black hole outside the central region of a galaxy. He could thus be none other than one of the former members of a triple of black holes which was well in the heart of the galaxy. Due to the chaotic nature of orbits At three bodies, one of them was expected and would now find himself wandering in his galaxy.
Thanks to the algorithm specially developed to distinguish, in data from Zwicky Transient Facilitythe shards from supernovae from those issued by TDEs, the researchers now hope to find other black supermassive holes like this. This would potentially allow them to calculate the frequency to which the galaxies and their central black holes merge. And so the time required for the formation of certain extreme supermassive black holes.
