Hubble images give Roman targets for studying dark matter
1 min readNASA published the announcement on Thursday 12 November 2026. The agency said Hubble images of gravitational lenses provide targets for follow-up observations by the Nancy Grace Roman Space Telescope. The images can also support research into dark matter.
Gravitational lensing occurs when the gravity of a massive foreground galaxy bends and magnifies light from a more distant background galaxy. The lenses in the Hubble image formed from the alignment of background galaxies with foreground galaxies. They created distorted arcs around the foreground galaxies.
Astronomers will use the observations to build lens models and determine the amount of mass in the foreground galaxies, including invisible dark matter. They will study the distortion of lensed background galaxies to determine the quantity and distribution of that mass.
Hubble provides high-resolution views of individual lenses in visible and ultraviolet light, with some infrared coverage. Roman observes primarily infrared light over a larger field of view. Roman can capture more lenses, while Hubble can examine interesting lenses in greater detail. The Hubble images are expected to yield results on dark matter and support analysis of Roman’s larger sample.
Researchers may detect small imperfections in gravitationally lensed galaxy arcs that indicate small clumps of dark matter. The cold dark matter theory predicts clumps of between a million to a billion solar masses. The dark matter halo of the Milky Way galaxy is around 1.3 trillion solar masses. Researchers also plan to build a tool for finding similar arcs in Roman images.
The gallery includes an arc-counterarc configuration, an Einstein Ring and quadruply lensed galaxies. Some background galaxies appear blue and others red, indicating young and older stars. The strong lenses were first detected with The Dark Energy Spectroscopic Instrument at Kitt Peak. Hubble observed them, and Roman will conduct further observations as part of NASA’s large space observatory programs.
