The James Webb Space Telescope has broken its own record, again!
Not to sound like a broken record, but records are made to be broken. And the James Webb Space Telescope has just accomplished one. But researchers happily caution: as with all such records, it won’t stand forever.
JADES-GS-z14-0 is now the most distant—and, therefore, the youngest—galaxy ever observed. Formed just 290 million years after the Big Bang (at two percent of the age of the cosmos), the galaxy spans some 1,600 light-years and is pouring out light. The JWST Advanced Deep Extragalactic Survey (JADES) team announced the finding last week.
Astronomers calculate distances to remote objects by measuring redshifts, a yardstick of how deeply stretched the galaxy’s light is (and redder means farther away). GS-z14-0 was discovered to have a redshift of 14.3, besting the 2022 record of a galaxy found with a redshift of 13.2 that corresponded to a formation age of some 325 million years after the Big Bang.
According to NASA, members of the JADES team explained recently that “the light we see is coming mostly from young stars and not from emission near a growing supermassive black hole. This much starlight implies that the galaxy is several hundreds of millions of times the mass of the Sun! This raises the question: How can nature make such a bright, massive, and large galaxy in less than 300 million years?”
The galaxy’s number of massive stars poses a dark-matter conundrum. Dark matter accumulates as the cosmos expands. Rieke says that “the problem with this galaxy is it’s pushing against what we think is the maximum mass for a dark halo at that time.”
The findings were made with JWST’s Near-Infrared Spectrograph, Near-Infrared Camera, and Mid-Infrared Instrument. In the latter case, researchers noted the irony that during the budget woes of JWST, the Mid-Infrared Instrument was frequently targeted for budget cuts. Now, along with its companion science packages, it’s targeting the earliest galaxies in the cosmos.
The findings from GS-z14-0 did not come easy. The team first observed the object more than a year ago, but its brightness and proximity to another galaxy was puzzling. While they had a preliminary redshift finding, the team later obtained a spectrum that confirmed the galaxy’s distance, along with its other puzzling properties, measurements that push but do not overturn models of stellar and galactic formation. The “naïve assumption,” said Helton, had been that these earlier galaxies would be smaller and fainter.
Certainly JADES-GS-z14-0 won’t be the record-holder forever. As time rolls on, astronomers are destined to find even more distant, younger galaxies. Meanwhile, work from this discovery, including that of Brant Robertson, a University of California Santa Cruz astronomer, will be appearing in Astrophysical Journal and is being reviewed by Nature and Nature Astronomy.