Project Goals
One of the biggest open questions in astrophysics is the origin of supermassive black holes—cosmic giants with millions to tens of billions of solar masses—that reside at the centers of nearly every massive galaxy observed. Even more puzzling, the first of these black holes appear to have formed and grown to enormous sizes within just a few hundred million years after the Big Bang. The BRAHMA cosmological simulation project seeks to unravel this mystery by investigating the birth and early growth of the universe’s very first black hole “seeds” within the evolving cosmic web. By combining state-of-the-art numerical simulations with insights from galaxy formation physics, BRAHMA bridges theory and observation. This is a pivotal moment: the James Webb Space Telescope (JWST) is uncovering the earliest luminous quasars in unprecedented detail, while the upcoming Laser Interferometer Space Antenna (LISA) will capture the gravitational wave signatures of their mergers. Together, these facilities will provide a transformative opportunity to test BRAHMA’s predictions and deepen our understanding of black hole origins.
New Models for Black Hole Seed Formation
The BRAHMA simulations use a novel and sophisticated prescription for black hole seed formation, incorporating the three leading theoretical scenarios: Population III stellar remnants, runaway collisions in nuclear star clusters (NSC), and direct collapse black holes.
Population III and Nuclear Star Cluster seeds are thought to form in dense, metal-poor regions of gas. In our simulations, we identify such regions to form the smallest black hole seeds our models can resolve.
Modeling Pop III or NSC seeds
Examples of PopIII/NSC seed formation sites in the BRAHMA simulations
Modeling DCBH seeds
DCBHs presumably form in rare regions where intense UV (Lyman–Werner) radiation suppresses molecular hydrogen cooling and star formation in dense, pristine gas. Our simulations create seeds in such environments.
Examples of DCBH seed formation sites in the BRAHMA simulations
