Astrophysical Anomalies from Hubble’s Archive

Six previously undiscovered, weird and fascinating astrophysical objects are displayed in this new image from NASA's Hubble Space Telescope. These were discovered by researchers from the European Space Agency using a new AI-assisted method. The AI tool allowed them to search nearly 100 million image cutouts and uncover objects with an unusual appearance including gravitational lenses; jellyfish galaxies with gaseous ‘tentacles’; merging and interacting galaxies; galaxies featuring rings, and arcs, and more.

This collection features six galaxies, showing a cross-section of the discoveries with some of the more striking examples: three lenses with arcs distorted by gravity, one galactic merger, one ring galaxy, and one galaxy — not alone in the results — which defied classification.

Top left: Collisional ring galaxy

This object was classified by the research team as a “collisional ring” galaxy — one of only two that were found. These are galaxies which are partly or wholly ring-shaped, but with a disrupted or bent disc that is noticeably luminous. These ring formations arise when a galaxy collides with another by crashing right through its center, creating a roiling, circular wave of star formation. Hubble has featured other collisional ring galaxies before, but the precise alignment between colliding galaxies needed to create them means they are quite rare, including in AI-assisted searches. This galaxy was not previously recorded.

Top middle: Gravitational lens 1

This oval-shaped galaxy is perhaps most striking for the long, thin beam of light stretching across its center. This is thought to be the result of a galaxy merger. A less conspicuous feature is the small arc of light just below the galaxy’s core. This is thought to be the secondary galaxy in the merger, or a potential image formed by gravitational lensing, where the mass of the foreground galaxy has bent light from a distant galaxy behind it to create the small arc of light.

Top right: Merging galaxies

A small collection of gravitationally interacting galaxies has been found here. Galaxy mergers are relatively common — they were the most abundant type of anomaly found by the researchers — and are easily identified by the distorted shapes of the galaxies’ disks and the tidal tails stretching out between them, caused by the massive gravitational forces slowly pulling each galaxy apart. Eventually the galaxies we see here will be totally disrupted and finally settle into the shape of a single galaxy, most likely an elliptical galaxy.

Bottom left: Unknown object

The strange, bi-polar galaxy seen here is certainly anomalous, with its compact, swirling core and two open lobes at the sides. Exactly what kind of galaxy it is is unclear, and it was not previously known to astronomers. It’s an example of the kinds of new and unusual finds that can be made by AI-assisted data processing, even from well-known datasets.

Bottom middle: Gravitational lens 2

This image depicts a gravitational lens, where the enormous mass of one galaxy distorts, bends and magnifies light from another galaxy behind it, resulting in a warped image of the background galaxy. The gravitational lens is easily identifiable here, with the lensed galaxy forming an arc around the dense core of the foreground, lensing galaxy.

Bottom right: Gravitational lens 3

Two dramatically different galaxies are revealed in this Hubble image. A compact, reddish elliptical galaxy is accompanied by a blue spiral galaxy squashed into an arc shape. This is the result of gravitational lensing, where light from the spiral galaxy — actually residing in the background — has been bent by the mass of the heavy elliptical galaxy, creating this distorted image of the spiral.