Over 1,000 “Winged” radio galaxies reveal a hidden architecture of cosmic jets

Astronomers have uncovered more than 1,000 radio galaxies with unusual “wings,” dramatically expanding a rare class of cosmic objects whose strange shapes may preserve the history of black hole activity, galaxy mergers, and the movement of plasma across intergalactic space.

The discovery comes from a systematic search using the LOFAR Two-meter Sky Survey Data Release 2, known as LoTSS DR2, one of the most powerful low-frequency radio surveys currently available. Instead of finding only a handful of rare examples, the team identified 1,024 new winged radio galaxies, including 621 confirmed systems with clear X-shaped or Z-shaped radio structures.

This result transforms winged radio galaxies from a small and unusual population into a large sample suitable for deeper statistical study.

Galaxies shaped by invisible engines

Radio galaxies are powered by supermassive black holes at the centers of galaxies. As matter falls toward the black hole, part of that energy can be redirected into enormous jets of charged particles moving outward in opposite directions.

These jets shine strongly in radio wavelengths and can extend across hundreds of thousands or even millions of light-years. In many radio galaxies, the result is a relatively simple double-lobed structure. But winged radio galaxies are different.

They show an additional pair of fainter radio extensions, known as wings. In some cases, these wings create an X-shaped pattern. In others, they bend into a Z-like structure. These forms suggest that the history of the central black hole and its surrounding environment may be more complex than a single, stable pair of jets.

X-shaped and Z-shaped cosmic fossils

The newly expanded catalog includes 382 confirmed X-shaped radio galaxies and 239 confirmed Z-shaped systems. Another 403 objects show possible winged features but remain less certain because their wings are faint, asymmetric, small, or partly hidden by projection effects.

The difference between these structures is not just visual. In X-shaped radio galaxies, the wings appear to emerge closer to the central region. In Z-shaped systems, the wings seem to branch from the outer parts of the main lobes.

These morphologies may point to different physical processes. One possibility is that the central black hole changed the direction of its jets, perhaps after a merger with another supermassive black hole. Another is that plasma from the main lobes flowed backward and was redirected by the surrounding medium. A third possibility involves more complex interactions between jets, gas, and the large-scale environment around the host galaxy.

A massive search through radio data

To build the catalog, the researchers examined LoTSS DR2, which contains more than 4.3 million radio sources. After applying a size-based selection, they narrowed the list to 204,789 candidates and then visually inspected the sources for winged structures.

This careful approach was necessary because winged radio galaxies are difficult to classify automatically. Their shapes can be distorted by viewing angle, sensitivity limits, environmental effects, and the faintness of the secondary lobes.

The result is one of the largest known samples of winged radio galaxies, offering astronomers a much stronger foundation for testing competing formation scenarios.

Some are enormous even by galactic standards

The study also found that many of these systems are physically huge. On average, the newly identified winged radio galaxies span about 1.6 million light-years.

Even more strikingly, 102 of them exceed 0.7 megaparsecs in size, or roughly 2.2 million light-years. That places them among candidates for giant radio galaxies, some of the largest individual structures produced by black hole activity in the universe.

This matters because giant radio galaxies can trace long-lived jet activity, low-density environments, and the cumulative influence of supermassive black holes over cosmic time.

Why this discovery matters

Winged radio galaxies are not merely curiosities. Their shapes may record dramatic events in the lives of galaxies: black hole mergers, jet reorientation, plasma backflow, or interactions with surrounding gas.

By expanding the known population to more than 1,000 systems, astronomers can now move beyond individual case studies. They can compare sizes, shapes, environments, host galaxies, and radio properties across a much broader sample.

The new catalog therefore opens a path toward understanding why some radio galaxies grow wings at all — and what those wings reveal about the hidden engines at the hearts of galaxies.

© 2026 SKYCR.ORG | Homer Dávila Gutiérrez, FRAS. All rights reserved. Total or partial reproduction without express authorization is prohibited. Original source: Phys.org; scientific source: Soumen Kumar Bera et al., “A Morphological Identification and Study of Radio Galaxies from LoTSS DR2. I. The ‘Winged’ Radio Galaxies”, arXiv, 2026. DOI: 10.48550/arXiv.2604.22347