Dark Matter Capture Achieves First Supermassive Black Holes at High Redshifts

The unexpectedly early appearance of supermassive black holes in the universe presents a significant puzzle for astronomers, challenging current theories of black hole formation. Sulagna Bhattacharya, Debajit Bose, and Basudeb Dasgupta, along with colleagues from the Tata Institute of Fundamental Research and the Indian Institute of Science, propose a novel explanation involving the capture of dark matter within the first generation of stars, known as Population III stars. Their research demonstrates that non-annihilating dark matter, interacting with normal matter, accumulates inside these stars, causing them to collapse directly into black hole seeds with masses comparable to the original star. This process offers a pathway for these seeds to grow rapidly into the supermassive black holes observed at very early cosmic times, and the team identifies specific properties of dark matter that would support this scenario, potentially detectable through upcoming experiments and gravitational wave observations.

Scientists propose a novel explanation involving the capture of dark matter within the first generation of stars, known as Population III stars.

Their research demonstrates that non-annihilating dark matter, interacting with normal matter, accumulates inside these stars, causing them to collapse directly into black hole seeds with masses comparable to the original star. This process offers a pathway for these seeds to grow rapidly into the supermassive black holes observed at very early cosmic times, and the team identifies specific properties of dark matter that would support this scenario, potentially detectable through upcoming experiments and gravitational wave observations.

Dark Matter Capture in Early Stars

The presence of supermassive black holes at high redshifts challenges standard black hole formation scenarios. This work proposes a mechanism whereby non-annihilating dark matter, with non-gravitational interactions, accumulates within Population III stars, dramatically increasing their mass and ultimately leading to the direct collapse of these stars into intermediate-mass black holes.

The team investigates the capture rate of dark matter particles by Population III stars, considering both accretion and the effects of dark matter self-interactions. Results demonstrate that, for a specific dark matter particle mass and interaction strength, a significant fraction of the stellar mass can be converted into dark matter within the star’s lifetime, creating a “dark matter core” that alters its structure and accelerates its evolution towards collapse.

The research further explores the subsequent growth of these seed black holes via accretion, showing that they can rapidly reach supermassive scales at the observed high redshifts. Specifically, a 100 solar mass seed black hole, formed through this dark matter capture mechanism, can grow to 10 6 solar masses by a specific redshift, consistent with the most distant quasars observed. The study highlights the potential for this novel pathway to explain the unexpectedly early appearance of supermassive black holes, offering a compelling alternative to conventional models.

Focusing on dark matter interactions, the team identifies regions of parameter space that account for the observed high-redshift supermassive black holes, their mass function, and the relationship between black hole and stellar mass. Portions of this parameter space are testable by forthcoming direct detection experiments and may lead to distinctive gravitational wave signatures from supermassive black hole mergers, accessible to future observatories.

Dark Matter Drives Early Black Hole Seeds

Scientists have proposed a new mechanism to explain the unexpectedly early appearance of supermassive black holes in the universe, a finding that challenges existing models of black hole formation. Their work centers on the idea that dark matter, rather than simply exerting gravitational pull, can interact with normal matter within the first generation of stars, known as Population III stars.

This interaction causes these stars to collapse prematurely into black hole seeds with masses equivalent to the original star, providing a pathway for rapid growth into the supermassive black holes observed at very high redshifts. The team’s calculations demonstrate that, with specific properties of dark matter interaction, this process can account for the observed population of high-redshift supermassive black holes, their distribution of masses, and the relationship between black hole mass and the mass of their host galaxies.

Importantly, the predicted ratios of black hole to stellar mass, particularly in smaller galaxies, offer a testable prediction for future astronomical surveys. Furthermore, the framework anticipates detectable gravitational wave signals from both individual black hole mergers and a background of gravitational waves, potentially within the reach of current and upcoming observatories. The authors acknowledge that their model relies on certain assumptions about the nature of dark matter and its interactions, which currently lie beyond the sensitivity of existing direct detection experiments, but highlight that portions of the parameter space explored are within the reach of forthcoming experiments, offering a potential avenue for validating the theory.