Astronomers Detect Primitive Galaxy Y1, Star Formation Rate 180 Times That of the Milky Way

An international consortium of astronomers announced on November 12, 2025, the identification of a primitive galaxy, designated Y1, which exhibits an astonishingly rapid rate of stellar birth. This galaxy is manufacturing new stars at an intensity 180 times greater than our own Milky Way. This finding offers crucial insights into the mechanisms driving the early evolution of galaxies across the cosmos. The observations were gathered using cutting-edge instruments, notably the Atacama Large Millimeter/submillimeter Array (ALMA) and the James Webb Space Telescope (JWST).

The light observed from Y1 has traversed a distance of 13.4 billion light-years. Consequently, scientists are viewing this galaxy as it existed only about 600 million years following the Big Bang. This discovery presents a significant challenge to established theoretical models concerning the early universe. These models generally did not anticipate the rapid assembly of such massive and luminous structures at such an ancient epoch. Key researchers leading this investigation include the primary author, Tom Bux from Chalmers University of Technology in Sweden, alongside co-authors Yoichi Tamura of Nagoya University and Laura Sommovigo.

Researchers confirmed the intense activity by detecting the emission lines from excited hydrogen and oxygen atoms, serving as a direct signature of high energy output. Tom Bux concluded that the radiation captured primarily originates from superheated cosmic dust, which effectively cloaks the vigorous star-forming process occurring within. This observation lends credence to the hypothesis that these types of 'superheated stellar factories' might have been a common, albeit fleeting, feature of the nascent universe. Analyzing the data, Yoichi Tamura pointed out that the measured temperature unequivocally confirms Y1 as a colossal engine of star production.

Measurements conducted by ALMA, utilizing a wavelength of 0.44 millimeters, determined the dust temperature within the galaxy to be approximately 90 Kelvins (roughly -180°C). While this temperature might seem relatively cool by terrestrial standards, it substantially outstrips the readings from any other comparable galaxy observed at the same cosmic age. Laura Sommovigo emphasized that the galaxy’s high luminosity stems from the exceptional efficiency of a small volume of hot dust in generating new stars, rather than being a product of numerous ancient stellar populations. This finding may finally resolve the long-standing mystery regarding the excess dust observed in young galaxies via JWST data, dust that previously seemed too abundant to have formed from older stars alone.

The significance of this breakthrough lies in its capacity to shake up current paradigms regarding universal evolution. The research team posits that galaxies operating at such extreme limits may have been far more prevalent in the early cosmos than previously accounted for. In this context, it is worth noting the galaxy J0107a, discovered in May 2025. J0107a, existing 11.1 billion years ago, boasted a mass over ten times that of the Milky Way and formed stars 300 times faster. However, unlike J0107a, whose growth spurt was fueled by rapid gas accretion toward its core, Y1 demonstrates its extreme performance through the sheer efficiency of its dusty component.

The combined datasets obtained through the cooperative efforts of JWST and ALMA underscore the indispensable nature of high-precision observations for accurately mapping the earliest structures in space. This study, which is slated for publication in the Monthly Notices of the Royal Astronomical Society, solidifies the view that we are peering into an era where the universe was significantly more dynamic in terms of star formation than earlier estimates suggested. The scientists are now planning follow-up observations utilizing ALMA’s highest resolution capabilities to probe the internal dynamics of Y1 and unravel the precise mechanisms driving this unprecedented stellar output.