Astronomers Discover Earliest Barred Spiral Galaxy, Rewriting Timeline of Galactic Evolution
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A groundbreaking discovery by astronomers has revealed the most distant barred spiral galaxy yet observed, offering unprecedented insight into the early universe and challenging existing theories of galactic formation. The finding, presented on January 8th, 2026, at the 247th meeting of the American Astronomical Society in Phoenix, Arizona, provides a crucial new data point for understanding how galaxies evolved in the cosmos’s infancy.
Unveiling COSMOS-74706: A Glimpse into the Distant Past
The research, spearheaded by Daniel Ivanov, a physics and astronomy graduate student at the University of Pittsburgh (UPitt), centers on a galaxy designated COSMOS-74706. Utilizing the advanced capabilities of the NASA/ESA/CSA James Webb Space Telescope (JWST), coupled with data from the Space Telescope Science Institute (STScI), Ivanov and his team identified the galaxy and subsequently confirmed its age with the multi-Object Spectrograph for Infrared Exploration (MOSFIRE) on the Keck I telescope. The analysis revealed that COSMOS-74706 existed over 11.5 billion years ago, making it the oldest spectroscopically confirmed barred spiral galaxy to date.
The Meaning of Barred Spirals
Galaxies, as categorized by the Hubble Sequence, are broadly classified as elliptical, spiral, or lenticular based on their structure.Spiral galaxies typically begin as irregular disks, evolving to exhibit characteristic spiral arms extending from a central bulge. Barred spirals, like our own Milky Way, possess a distinct bar-shaped structure at their core, composed of stars. This bar plays a vital role in galactic evolution, channeling gas inward to fuel the supermassive black hole at the center and regulating star formation throughout the galactic disk.
Refining the Timeline of Galactic Progress
Previous claims of identifying older barred spiral galaxies have been met with skepticism due to limitations in observational methods. Techniques like gravitational lensing, while capable of magnifying distant objects, can distort the light, introducing uncertainty. Similarly,redshift measurements,which estimate distance based on the stretching of light waves,are prone to errors of 10-15%.However, the team’s use of spectroscopy – analyzing the light spectrum emitted by the galaxy – provided a definitive validation of COSMOS-74706’s age.
“This galaxy was developing bars 2 billion years after the birth of the Universe.Two billion years after the Big Bang,” Ivanov stated in a UPitt press release. “It’s the highest redshift, spectroscopically confirmed, unlensed barred spiral galaxy. In principle, I think that this is not an epoch in which you expect to find many of these objects. It helps to constrain the timescales of bar formation. And it’s just really engaging.”
Simulations and Observational Evidence converge
While theoretical simulations have suggested that bars could have formed in galaxies as early as 12.5 billion years ago,concrete observational evidence has remained elusive. The discovery of COSMOS-74706 bridges this gap, providing crucial support for these models and helping to refine our understanding of the processes that shaped the early universe. This finding suggests that the formation of barred spiral structures may have been more common in the early universe than previously thought.
The original version of this article was published on Universe Today.
