Supermassive black holes could form from dark matter

Exactly how supermassive black holes initially formed is one of the biggest problems in the study of galaxy evolution today. Supermassive black holes have been observed as early as 800 million years after the Big Bang, and how they could grow so quickly remains unexplained.

Standard formation models involve normal baryonic matter — the atoms and elements that that make up stars, planets, and all visible objects — collapsing under gravity to form black holes, which then grow over time. However the new work investigates the potential existence of stable galactic cores made of dark matter, and surrounded by a diluted dark matter halo, finding that the centres of these structures could become so concentrated that they could also collapse into supermassive black holes once a critical threshold is reached.

According to the model this could have happened much more quickly than other proposed formation mechanisms, and would have allowed supermassive black holes in the early Universe to form before the galaxies they inhabit, contrary to current understanding.

Carlos R. Argüelles, the researcher at Universidad Nacional de La Plata and ICRANet who led the investigation comments: “This new formation scenario may offer a natural explanation for how supermassive black holes formed in the early Universe, without requiring prior star formation or needing to invoke seed black holes with unrealistic accretion rates.”

Another intriguing consequence of the new model is that the critical mass for collapse into a black hole might not be reached for smaller dark matter halos, for example those surrounding some dwarf galaxies. The authors suggest that this then might leave smaller dwarf galaxies with a central dark matter nucleus rather than the expected black hole. Such a dark matter core could still mimic the gravitational signatures of a conventional central black hole, whilst the dark matter outer halo could also explain the observed galaxy rotation curves.

“This model shows how dark matter haloes could harbour dense concentrations at their centres, which may play a crucial role in helping to understand the formation of supermassive black holes,” added Carlos.

“Here we’ve proven for the first time that such core-halo dark matter distributions can indeed form in a cosmological framework, and remain stable for the lifetime of the Universe.”

The authors hope that further studies will shed more light on supermassive black hole formation in the very earliest days of our Universe, as well as investigating whether the centres of non-active galaxies, including our own Milky Way, may play host to these dense dark matter cores.

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Materials provided by Royal Astronomical SocietyNote: Content may be edited for style and length.

Fifth dimension could help to unravel the mysteries of dark matter

ZME Science

In early 1920s, in an effort to unify the forces of gravity and electromagnetism, Theodor Kaluza and Oskar Klein speculated about the existence of an additional dimension beyond the familiar three space dimensions and time — which in physics are combined into 4-dimensional spacetime. If it exists, such a replacement dimension would need to be incredible tiny and unnoticeable to the human eye. within the late 1990s this concept has seen an interesting renaissance, when it had been realized that the existence of a fifth dimension could resolve a number of the profound open questions of high-energy physics . especially , Yuval Grossman of Stanford University and Matthias Neubert, then a professor at Cornell University , showed during a highly cited publication that the embedding of the quality Model of high-energy physics during a 5-dimensional spacetime could explain the thus far mysterious patterns seen within the masses of elementary particles.

Another 20 years later, the group of Matthias Neubert — since 2006 on the school of Gutenberg University in Mainz (Germany) and spokesperson of the PRISMA+ Cluster of Excellence — made another unexpected discovery: they found that the 5-dimensional field equations predicted the existence of a replacement , baryon with similar properties because the famous Higgs boson but a way heavier mass — so heavy, in fact, that it can’t be produced even at the highest-energy particle collider within the world: the massive Hadron Collider (LHC) at the ecu Center for Nuclear Research CERN near Geneva (Switzerland). “It was a nightmare,” recalls Javier Castellano Ruiz, a PhD student involved within the research, “we were excited by the thought that our theory predicts a replacement particle, but it seemed to be impossible to verify this prediction in any foreseeable experiment.”

The detour through the fifth dimension

In a recent paper published within the European Physical Journal C, the researchers found a spectacular resolution to the present dilemma. they found that their proposed particle would necessarily mediate a replacement force between the known elementary particles (our visible universe) and therefore the mysterious substance (the dark sector). Even the abundance of substance within the cosmos, as observed in astrophysical experiments, are often explained by their theory. This offers exciting new ways to look for the constituents of the substance — literally via a detour through the additional dimension — and acquire clues about the physics at a really early stage within the history of our universe, when the substance was produced. “After years of checking out possible confirmations of our theoretical predictions, we are now confident that the mechanism we’ve discovered would make the substance accessible to forthcoming experiments, because the properties of the new interaction between ordinary matter and substance — which is mediated by our proposed particle — are often calculated accurately within our theory” says Matthias Neubert, head of the research team. “In the top — so our hope — the new particle could also be discovered first through its interactions with the dark sector.” this instance nicely illustrates the fruitful interplay between experimental and theoretical basic science — an indicator of the PRISMA+ Cluster of Excellence.

Materials provided by Johannes Gutenberg Universitaet Mainz.

Adrian Carmona, Javier Castellano Ruiz, Matthias Neubert. A warped scalar portal to fermionic dark matterThe European Physical Journal C, 2021; 81 (1) DOI: 10.1140/epjc/s10052-021-08851-0