Hubble Takes Gravitational Lens Images for Roman Groundwork

NASA's Hubble Space Telescope has taken gravitational lensing images.

Astronomers will use them to analyze dark matter and lay groundwork for observations by the Nancy Grace Roman Space Telescope.

Gravitational lensing happens when foreground mass bends spacetime, and lenses require a chance alignment between foreground and background galaxies.

The foreground elliptical galaxy is about 4.5 billion light-years away, and its light began traveling while the solar system was still forming.

The lensed background galaxy lies about eight billion light-years away, and the arcs form an arc-counterarc pair.

A more massive foreground galaxy creates a stronger gravitational lens, and researchers can determine the foreground galaxy's mass from the background galaxy's distortion.

Dark matter accounts for most of the universe's mass, and visible matter is not enough to account for the background galaxy's distortion.

Almost all objects in the image are galaxies, except a few scattered foreground stars.

A barred spiral galaxy in the image is about the size of the Milky Way, and a tiny spiral may be a satellite galaxy.

Gravitational lenses let researchers determine the mass of a foreground galaxy from distortion of a background galaxy.

Visible matter alone cannot explain that distortion, while dark matter accounts for most of the universe's mass.

Hubble's high-resolution views of individual objects and Roman's much larger field of view will support different parts of gravitational lens observations, and the telescopes will work together.

Astronomers will use the lens images to analyze dark matter and to lay groundwork for Roman observations.

They are using Hubble's sharp images to build a computer model that will help analyze Roman's large images.

Hubble will work with Roman, follow up on interesting lenses Roman detects, and Roman's wide view of the sky will provide a larger sample of gravitational lenses.