A new study by computational astrophysicist Ethan Nadler from the University of California, San Diego, shows that star formation can occur at halos in the solar masses of 10 million people through molecular hydrogen cooling.
Nadler calculated the percentage of dark matter halos above the critical mass required for star formation. Image credit: Xiaodian Chen.
All galaxies are thought to form at the center of the dark matter halo. This is a region of material coupled to gravity that extends far beyond the galaxy’s visible boundary.
Stars form when gravity within the halo of dark matter draws gases, but astrophysicists still don’t know if there is a dark halo of matter without stars.
“What is the halo mass threshold for the galaxy layer?” said Dr. Nadler.
“This question underlies the key areas of research in galaxy formation and cosmology, including when and how the first galaxy was formed, how galaxies promote the regeneration of the universe, and whether halos of “dark” (without galaxies) exist.
“Robust predictions of galaxy formation thresholds are important to provide future observations of faint galaxies and low-mass halos throughout the history of the universe.”
In his new study, Dr. Nadler calculated the mass that Halo cannot form stars.
His research was conducted using analytical predictions from galaxy formation theory and cosmological simulations.
“Historically, understanding of dark matter has been related to behavior in the galaxy,” Dr. Nadler said.
“When you detect a completely dark halo, a new window opens to study the universe.”
Previously, this threshold for star formation was thought to be between 100 million and 1 billion solar masses due to cooling of atomic hydrogen gas.
The current study shows that star formation can occur in the solar mass of 10 million people at halos via molecular hydrogen cooling.
“The Rubin Observatory will be coming online later this year and Webb is already making unprecedented observations of our universe, so we’ll soon have new data to test these predictions, revealing whether there’s a completely dark halo,” Dr. Nadler said.
“This could have widespread consequences for cosmology and the nature of dark matter.”
study It will be displayed in Astrophysics Journal Letter.
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Ethan O. Nadler. 2025. Effect of molecular hydrogen cooling on galaxy formation thresholds. apjl 983, L23; doi:10.3847/2041-8213/adbc6e
Source: www.sci.news
