New computational study reveals that star formation is possible in dark matter halos much smaller than previously estimated, pointing to the existence of completely dark halos as a challenge to early universe cosmology
Every galaxy is thought to form at the center of a dark matter halo—a region of gravitationally bound matter that extends far beyond the visible boundaries of the galaxy. Stars form when gravity within a dark matter halo pulls in gas, but astrophysicists don't yet know whether dark matter halos exist without stars.
Eitan Nadler, a computational astrophysicist in San Diego, recently calculated the mass below which halos do not form stars. This work was done using analytical predictions from galaxy formation theory and cosmological simulations.
"Historically, our understanding of dark matter has been tied to its behavior in galaxies. The discovery of completely dark halos would open a new window in the study of the universe," said Nadler.
Previously, this threshold for star formation was thought to be between 100 million and a billion solar masses due to the cooling of atomic hydrogen gas. Nadler's research shows that star formation can occur in haloes as small as XNUMX million solar masses through the cooling of molecular hydrogen.
With the Rubin Observatory set to begin operations later this year and the James Webb Space Telescope already making unprecedented observations of our universe, new data will soon be available to test these predictions and discover whether completely dark halos exist. This could have far-reaching implications for cosmology and the nature of dark matter.
More of the topic in Hayadan:
