Astrophysics

A massive barred spiral galaxy at z = 5.102 discovered by JWST

Xiaohan Wang, et al.

Featured July 7, 2026

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Simply

Astronomers found a galaxy with a bar-shaped center and swirling arms far, far away, from when the universe was very young, showing that complex galaxies formed much earlier than thought.

In depth

This paper reports the discovery of M1149-BSG-z5, a barred spiral galaxy at a redshift of

z = 5.102

, making it the highest-redshift candidate found to date. The authors used JWST and HST observations, employing ellipse isophote fitting and structural modeling to confirm the presence of a stellar bar and extended spiral arms. This early emergence of a complex galaxy structure challenges conventional models of galaxy formation and evolution, suggesting that conditions for such structures were established much earlier in the Universe.

Key Takeaways

1
The discovery of M1149-BSG-z5 at $z = 5.102$ represents the highest-redshift barred spiral galaxy candidate, pushing the observational frontier for complex galaxy structures.
2
The galaxy exhibits a large stellar bar (length $a_{ba r} \approx 4.5$ kpc) and extended spiral arms, identified through ellipse isophote fitting and structural decomposition, indicating an early-assembled and structurally evolved system.
3
M1149-BSG-z5 is a massive, star-forming galaxy with an active galactic nucleus (AGN) and metal-enriched gas, suggesting it is a chemically evolved system already in place at $z \sim 5$ .

Conceptual Flow

HIGH LEVEL

Methodology: Finding Distant Galaxies

Scientists used powerful telescopes to take many pictures of the sky, then measured how light from distant galaxies was stretched to figure out how far away they are and what they look like.

Telescope Images

Light Wavelengths

Measure & Analyze

Galaxy Distance

Galaxy Shape

Results: An Unexpected Early Bar

They found a galaxy with a bar shape that is much older and farther away than expected, meaning big, organized galaxies formed surprisingly early in the universe's history.

Old Ideas: Late Bars

New Telescope Data

Discover & Confirm

Early Barred Galaxy

New Galaxy Timeline