Turbulent disk gas swirling around a black hole. Credit: NASA’s Goddard Space Flight Center / Jeremy Schnittman
A new theoretical study has proposed a new mechanism to create supermassive black holes from dark matter. The international team finds that supermassive black holes, instead of the conventional formation scenarios with ‘normal’ matter, can form directly from dark matter in high-density regions in the centers of galaxies. The result has important implications for cosmology in the early universe, and is published in Monthly notices from the Royal Astronomical Society.
Exactly how supermassive black holes were initially formed is one of the biggest problems in the study of the evolution of the galaxy. Supermassive black holes were observed 800 million years later Big explosion, and how they could grow so fast remains unexplained.
Standard formation models involve normal baronic matter – the atoms and elements that make up stars, planets, and all visible objects – that collapse under gravity to form black holes, which then grow over time. However, the new work investigates the possible existence of stable galactic nuclei made of dark matter, and surrounded by a dilute dark matter halo, and finds that the centers of these structures can become so concentrated that they can also be in supermassive black holes. collapses as soon as it is critical. threshold is reached.
The artist’s impression of a spiral galaxy embedded in a larger distribution of invisible dark matter, known as a dark matter glory (colored in blue). Studies looking at the formation of dark matter rays have suggested that each halo may contain a very dense core of dark matter, which may mimic the effects of a central black hole or eventually collapse to form one. . Credit: ESO / L. Calçada
According to the model, this could happen much faster than other proposed formation mechanisms, and would allow supermassive black holes to form in the early universe in front of the galaxies in which they live, contrary to current understanding.
Carlos R. Argüelles, the researcher at the Universidad Nacional de La Plata and ICRANet who led the study, says: ‘This new formation scenario provides a natural explanation for how supermassive black holes formed in the early Universe, without requiring prior star formation. or to be required to call seed black holes with unrealistic growth. ‘
Another interesting consequence of the new model is that the critical mass for collapse in a black hole may not be reached for smaller dark matter radiation, for example those around some dwarf systems. The authors suggest that smaller dwarf systems may then leave a central core of dark matter, rather than the expected black hole. Such a dark matter core can still mimic the gravitational signatures of a conventional central black hole, while the outer halo of dark matter can also explain the observed galaxy curves.
“This model shows how dark matter hauls can contain dense concentrations in their centers, which can play an important role in understanding the formation of supermassive black holes,” Carlos added.
“Here we have proved for the first time that such a nuclear halo distribution of dark matter can indeed form within a cosmological framework, and can remain stable for the life of the universe.”
The authors hope that further studies will shed more light on supermassive formation of black holes in the earliest days of our universe, as well as to investigate whether the centers of inactive galaxies, including our own Milky Way, can host these dense dark matter nuclei.
Reference: “On the formation and stability of fermionic dark matter hauls in a cosmological framework” by Carlos R Argüelles, Manuel I Díaz, Andreas Krut and Rafael Yunis, 31 December 2020, Monthly notices from the Royal Astronomical Society.
DOI: 10.1093 / mnras / staa3986