A new study published in Astronomy & Astrophysics presents an innovative way to determine the size of dark matter halos —the enormous invisible structures that host galaxies— using only the size of galaxies in deep astronomical images.
Researchers Ignacio Trujillo and Claudio Dalla Vecchia, from the Institute of Astrophysics of the Canary Islands (IAC) and the University of La Laguna (ULL), have demonstrated that the size of a galaxy can serve as a very precise indicator of the size of its halo, offering measurements up to six times more accurate than those obtained with previous methods.
From the advanced cosmological simulations EAGLE, the team demonstrated that when a galaxy's size is defined by the exact point at which it stops producing new stars, this almost perfectly coincides with the size of its dark matter halo. The finding opens a new avenue for mapping dark matter in the Universe.
"We are entering a new era of deep astronomical observations, where the faintest edges of galaxies are becoming visible," points out Ignacio Trujillo. "These observations are powerful tools that allow us to explore the properties of the dark matter halos that shape galaxies with unprecedented precision," he adds"Numerical simulations have reached a level where they can robustly predict how galaxy sizes relate to their halos," explains Claudio Dalla Vecchia. "This predictive power gives us the confidence that we can use observational data to infer the invisible dark matter structures with extraordinary precision," he highlights.
The results suggest that, through the analysis of deep imaging studies, the distribution and properties of dark matter halos can be mapped with greater accuracy than ever before throughout cosmic time.