Astronomers have made a groundbreaking discovery using the James Webb Space Telescope (JWST) – they have detected the oldest dormant galaxy ever observed. This ancient galaxy ceased star formation at a mere 700 million years of age, a period when numerous stars were actively being born across the universe due to abundant gas and dust reserves.
The galaxy, labeled JADES-GS-z7-01-QU and detailed in a recent publication in the journal Nature, offers a rare insight into the fundamental mechanisms of galaxy evolution during the early stages of the universe. It raises questions about why galaxies cease to produce new stars and whether the factors influencing their star-forming activities evolve.
Lead researcher Tobias Looser from the University of Cambridge’s Kavli Institute for Cosmology mentioned that galaxies require a plentiful supply of gas to generate new stars, and during the early universe, this essential resource was abundant, akin to an ‘all-you-can-eat buffet’.
The newfound galaxy challenges existing models by not only emerging shortly after the Big Bang but also by promptly halting its star formation process. In contrast, other dormant galaxies discovered in different regions of the cosmos paused their star-forming activities around 3 billion years after the Big Bang.
The discovery of JADES-GS-z7-01-QU was made possible through the JWST’s advanced infrared capabilities, enabling researchers to penetrate the dense dust veils enshrouding the universe’s earliest formations. This galaxy, besides being the oldest dormant galaxy identified to date, is considerably lighter than similar inactive galaxies from the early universe.
The abrupt cessation of star formation in the galaxy, after a period of intense activity lasting between 30 to 90 million years, remains a mystery. Various factors could contribute to this phenomenon, such as internal turbulence or radiation from supermassive black holes depleting the gas reservoir necessary for star formation.
Co-author Roberto Maiolino mentioned that the characteristics of JADES-GS-z7-01-QU challenge current models based on the modern universe, indicating a potential need for their reassessment. One plausible explanation proposed is the cyclic nature of galaxies in the early universe, where dormant galaxies might undergo reactivation. However, earlier studies have indicated that ‘dead’ galaxies from a later epoch cannot revive even through interactions with neighboring galaxies.
Further observations are essential to unravel the mysteries surrounding this ancient inactive galaxy and its implications for our understanding of cosmic evolution.
