Groundbreaking research unveils innovative method to probe dark matter using gravitational lensing

Mariah Rosales

In a groundbreaking research initiative led by University of New Mexico (UNM) Physics PhD candidate Birendra Dhanasingham, supervised by UNM Physics professor Francis-Yan Cyr-Racine, unveiled a novel approach to unravel the mysteries of dark matter using gravitational lensing, a phenomenon predicted by Einstein's theory of relativity.

Interlopers speak out: studying the dark universe using small-scale lensing anisotropies focuses on the exploration of gravitational lensing, wherein massive celestial bodies, such as galaxies, act as lenses, bending light from sources located behind them. This bending creates multiple images, rings, arcs, and distortions of objects beyond the lens. The team's primary objective is to employ this lensing effect to study dark matter, which constitutes a staggering 85% of the universe's matter but remains elusive due to its non-interaction with light, rendering it directly unobservable.

Dark matter forms clumps known as "halos" on the scale of galaxies, and the research hones in on understanding the impact of these dark matter halos on the lensing of light from distant celestial objects like quasars and galaxies. The team introduces an innovative method termed "effective multiplane gravitational lensing" to analyze the mass distribution of all objects, including subhalos within the halo of a large lens galaxy and line-of-sight dark matter halos.

This pioneering method unveils that line-of-sight halos generate distinctive arc-shaped patterns when projecting the mass distribution onto a single map between the observer and the source, indicating a non-uniform mass distribution in different directions. The team measures how masses cluster in various directions, identifying unique signatures from line-of-sight dark matter halos that could potentially be detected by future extremely large telescopes.

Dhanasingham emphasizes the significance of the current "Golden Age" of cosmology, leveraging high-precision data from space-based assets like the Hubble Space Telescope and the upcoming James Webb Space Telescope, Vera C. Rubin Observatory, and Nancy Grace Roman Space Telescope. Dhanasignham says, “These advancements allow us to finely constrain the properties of our Universe. To tackle profound questions, such as the nature of dark matter, creative methods are essential.” Integrating this novel approach with artificial intelligence opens new avenues to address significant inquiries about the nature of dark matter in the era of big data.

Cyr-Racine highlights the need for creative methods to tackle questions surrounding dark matter's nature, and says, "The technique developed as part of this work has the potential to determine key properties of dark matter in a way that is complementary to other approaches.”

To probe the nature of dark matter using this methodology, the team simulated thousands of realistic strong lens systems, each with thousands of dark matter subhalos and line-of-sight halos, alongside their respective projected mass density maps. Given the computational demands of the two-point function for each map, the team used the Center for Advanced Research Computing resources to expedite the analysis.

In the pursuit of unraveling dark matter's mysteries, this research has made a significant leap in Dhanasingh and Cyr-Racine’s astrophysical understanding. Set against the backdrop of a 'Golden Age' of cosmology and leveraging cutting-edge technologies, the innovative "effective multiplane gravitational lensing" method, coupled with artificial intelligence, emerges as a promising beacon in cosmic exploration. This work not only illuminates the elusive properties of dark matter but also exemplifies the boundless potential of human ingenuity to redefine the limits of our understanding of the universe.