In the vast expanse of the universe, galaxies form at the core of dark matter halos—gravitationally bound regions extending far beyond a galaxy’s visible boundaries. These halos are key players in star formation, as their gravitational pull gathers gas to create stellar nurseries.
However, a lingering question remains: can dark matter halos exist without stars?
Ethan Nadler, a computational astrophysicist at UC San Diego, may have found an answer. Using analytic predictions from galaxy formation theory and advanced cosmological simulations, Nadler calculated the mass threshold below which dark matter halos fail to form stars.
While previously thought to range between 100 million and 1 billion solar masses due to the cooling of atomic hydrogen gas, Nadler’s research reveals that molecular hydrogen cooling enables star formation in halos as small as 10 million solar masses.
This groundbreaking discovery comes at a pivotal time. The Rubin Observatory will launch later this year, and the James Webb Space Telescope (JWST), already revolutionizing our view of the cosmos, will soon provide unprecedented data to test Nadler’s predictions. If completely star-free halos are identified, it could redefine our understanding of cosmology and shed new light on the enigmatic nature of dark matter.
Nadler emphasizes the potential impact: “A detection of completely dark halos would open up a new window to study the universe.”
The research highlights the dynamic interplay between cosmic gas, gravity, and dark matter—setting the stage for discoveries that could reshape astrophysics as we know it.
Journal Reference:
- Ethan O. Nadler. The Impact of Molecular Hydrogen Cooling on the Galaxy Formation Threshold. The Astrophysical Journal Letters. DOI 10.3847/2041-8213/adbc6e
Source: Tech Explorist
