A galaxy that all of a sudden stopped forming new stars greater than 13 billion years in the past has been noticed by astronomers.
Utilizing the James Webb House Telescope, a world workforce of astronomers led by the College of Cambridge have noticed a ‘lifeless’ galaxy when the universe was simply 700 million years previous, the oldest such galaxy ever noticed.
This galaxy seems to have lived quick and died younger: star formation occurred rapidly and stopped virtually as rapidly, which is sudden for therefore early within the universe’s evolution. Nevertheless, it’s unclear whether or not this galaxy’s ‘quenched’ state is momentary or everlasting, and what prompted it to cease forming new stars.
The outcomes, reported within the journal Nature, could possibly be necessary to assist astronomers perceive how and why galaxies cease forming new stars, and whether or not the components affecting star formation have modified over billions of years.
“The primary few hundred million years of the universe was a really lively part, with a lot of gasoline clouds collapsing to kind new stars,” mentioned Tobias Looser from the Kavli Institute for Cosmology, the paper’s first creator. “Galaxies want a wealthy provide of gasoline to kind new stars, and the early universe was like an all-you-can-eat buffet.”
“It is solely later within the universe that we begin to see galaxies cease forming stars, whether or not that is attributable to a black gap or one thing else,” mentioned co-author Dr Francesco D’Eugenio, additionally from the Kavli Institute for Cosmology.
Astronomers imagine that star formation could be slowed or stopped by various factors, all of which is able to starve a galaxy of the gasoline it must kind new stars. Inside components, reminiscent of a supermassive black gap or suggestions from star formation, can push gasoline out of the galaxy, inflicting star formation to cease quickly. Alternatively, gasoline could be consumed in a short time by star formation, with out being promptly replenished by recent gasoline from the environment of the galaxy, leading to galaxy hunger.
“We’re undecided if any of these situations can clarify what we have now seen with Webb,” mentioned co-author Professor Roberto Maiolino. “Till now, to know the early universe, we have used fashions based mostly on the trendy universe. However now that we will see a lot additional again in time, and observe that the star formation was quenched so quickly on this galaxy, fashions based mostly on the trendy universe might should be revisited.”
Utilizing information from JADES (JWST Superior Deep Extragalactic Survey), the astronomers decided that this galaxy skilled a brief and intense interval of star formation over a interval between 30 and 90 million years. However between 10 and 20 million years earlier than the time limit the place it was noticed with Webb, star formation all of a sudden stopped.
“All the things appears to occur sooner and extra dramatically within the early universe, and which may embody galaxies transferring from a star-forming part to dormant or quenched,” mentioned Looser.
Astronomers have beforehand noticed lifeless galaxies within the early universe, however this galaxy is the oldest but — simply 700 million years after the large bang, greater than 13 billion years in the past. This remark is among the deepest but made with Webb.
Along with the oldest, this galaxy can be comparatively low mass — about the identical because the Small Magellanic Cloud (SMC), a dwarf galaxy close to the Milky Manner, though the SMC continues to be forming new stars. Different quenched galaxies within the early universe have been way more huge, however Webb’s improved sensitivity permits smaller and fainter galaxies to be noticed and analysed.
The astronomers say that though it seems lifeless on the time of remark, it is attainable that within the roughly 13 billion years since, this galaxy might have come again to life and began forming new stars once more.
“We’re searching for different galaxies like this one within the early universe, which is able to assist us place some constraints on how and why galaxies cease forming new stars,” mentioned D’Eugenio. “It could possibly be the case that galaxies within the early universe ‘die’ after which burst again to life — we’ll want extra observations to assist us determine that out.”
The analysis was supported partially by the European Analysis Council, the Royal Society, and the Science and Know-how Amenities Council (STFC), a part of UK Analysis and Innovation (UKRI).
