The galaxy died earlier than expected

For a long time, scientists believed that only positive star galaxies could be observed in the early universe.

James Webb Space Telescope now reveals that the galaxy has stopped stars earlier than expected. The latest discovery from an international team led by astronomers at the University of Geneva (Unige) deepens the tension between theoretical models of universe evolution and practical observations. Among the hundreds of spectra obtained using the Webb program Rubies, the team discovered a record-breaking galaxy that had stopped forming stars in a period of galaxies, during which galaxies usually grow very rapidly. The study was published in the journal Astrophysics.

In the early universe, typical galaxies would accumulate gas from surrounding interlayer media and turn gas into stars. This process increases mass, resulting in more efficient gas accumulation and accelerates star formation. But galaxies don’t grow indefinitely because technology astronomers call “quenching.”

In the local universe, about half of the observed galaxies stop forming stars – they have stopped and stopped growing. Astronomers call them static, quenched or “red and dead” galaxies. They look red because they no longer contain young, bright blue stars – only older smaller red stars.

Especially high static galaxies are found in large galaxies, and they are usually observed to have an elliptical morphology. It usually takes a long time to form such red and dead galaxies, as they must first build a large number of stars before they can finally close. This remains a major problem, and is actually what causes quenching in galaxies. “It is crucial to find the first example of large-scale still galaxies (MQGs) in the early universe because it illuminates the possible mechanisms of their formation,” said Pascal Oesch, associate professor at the Unige Facutly Facutly face of Science and Coper of toper on the prestigious committee of Science and Science. Therefore, people have been the main goal of astronomers for many years.

Observation and theoretical expectations are inconsistent

With the development of technology, especially near-infrared spectroscopy, astronomers have confirmed large-scale static galaxies (MQGs) in an increasingly early cosmic era. Their inferred abundance reconciliation with theoretical models of galaxy formation is challenging, which predict that such systems should take longer to form. With the James Webb Space Telescope (JWST), this tension has been pushed to a red shift of 5 speeds (1.2 billion years after the Big Bang), several MQGs have been confirmed in recent years. New research led by Unige shows that these galaxies are forming even faster and faster than previously thought.

In JWST Cycle 2, the vast area plan Ruby (Red Unknown: Bright Infrared Breast Cancer Survey) is one of the largest European-led research programs using NIRSPEC instruments, and has obtained spectral observations from thousands of galaxies, including hundreds of newly discovered news sources from early JWST JWST.

Record holder “dead” the galaxy

Among these novel spectra, scientists identified the most distant MQG discovered so far, with a spectral redshift of 729, about 700 million years after the Big Bang. The NIRSPEC/PRISM spectrum reveals a surprisingly old star population in such a young universe. Detailed modeling of spectrum and imaging data shows that in the first 600 million years after the Big Bang, galaxies formed more than 10 billion (10⁰) of solar mass before rapidly stopping star formation, ensuring their static properties.

“The discovery of this galaxy, called Rubies-uds-QG-Z7, means that in the first billion years of the universe, large-scale static galaxies are more than 100 times higher than any model so far than any model expected,” Andrea Weibel, Science Acternomy of Science Accipty of Science and Capper of Paper of Paper of Paper of Paper of Paper of Paper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper of Capper. This, in turn, suggests that it may be necessary to revisit key factors in theoretical models (e.g., the effects of stellar winds and the outflow intensity powered by star formation and huge black holes). Galaxy deaths were much earlier than those models predicted.

Insight into the core of giant galaxies

Finally, the physical size of the ruby-UDS-QG-Z7 measured at ~650 light years is smaller, meaning that the high stellar mass density is comparable to the highest central density observed in static galaxies, slightly lower (Z ~ 2-5). These galaxies may evolve into the core of the oldest and largest elliptical galaxy in the local universe. “The discovery of Rubies-uds-QG-Z7 provides the first strong evidence that the centers of some nearby large elliptical machines may have been in place for the first few hundred million years of the universe,” concluded Anna De Graaff, principal investigator of the Rubies program.