Astronomers have identified one of the earliest known barred spiral galaxies ever observed, a structured cosmic object that was already forming when the universe was just 2 billion years old. The galaxy, designated COSMOS-74706, dates back approximately 11.5 billion years and contains a stellar bar strikingly similar to the one at the center of the Milky Way.
The discovery was led by Daniel Ivanov, a physics and astronomy graduate student at the University of Pittsburgh’s Kenneth P. Dietrich School of Arts and Sciences. Ivanov presented the findings at the 247th meeting of the American Astronomical Society.
What Makes This Galaxy Significant
A stellar bar is a straight, elongated band of tightly packed stars and gas that cuts across the central region of a spiral galaxy. When viewed from above, it appears as a bright line through the galaxy’s core. These structures do more than define a galaxy’s shape. They channel gas from outer regions inward, which can feed a supermassive black hole at the center and slow star formation across the surrounding disk.
Finding such a mature, organized structure this early in cosmic history raises questions about how quickly galaxies can develop complex internal architecture. “This galaxy was developing bars 2 billion years after the birth of the universe,” Ivanov said. “Two billion years after the Big Bang.”
Why the Confirmation Carries Weight
Other research teams have previously reported possible barred spiral galaxies from comparably early periods, but those findings depended on less precise redshift measurements. COSMOS-74706 was confirmed using spectroscopy, which produces more reliable distance data.
Earlier candidates also suffered from another complication: gravitational lensing, where light from a distant galaxy is distorted by a massive object positioned between it and Earth. COSMOS-74706 does not carry that distortion. As Ivanov put it, the galaxy is “the highest redshift, spectroscopically confirmed, unlensed barred spiral galaxy.”
That combination of precision and clarity sets it apart from prior claims in the field.
What Computer Simulations Predicted
The find is not entirely out of step with theoretical expectations. Computer simulations have suggested that stellar bars could begin forming as early as redshift 5, which corresponds to roughly 12.5 billion years ago. COSMOS-74706 sits at a somewhat later point in that window.
Still, Ivanov noted that such objects are not expected to appear frequently at this stage of cosmic history. “In principle, I think that this is not an epoch in which you expect to find many of these objects,” he said. “It helps to constrain the timescales of bar formation. And it’s just really interesting.”
The Role of James Webb
The research relied substantially on data from the NASA/ESA/CSA James Webb Space Telescope, processed through the Space Telescope Science Institute under NASA contract NAS 5-03127. The Brinson Foundation also provided project support.
Webb’s infrared sensitivity allows it to observe light from galaxies so distant and redshifted that earlier telescopes simply could not resolve them with enough detail. COSMOS-74706 is one of a growing number of early-universe structures that Webb is forcing astronomers to examine more closely, not because they were impossible to predict, but because they are now, finally, possible to see.
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