How did the James Webb telescope look back in time to redefine cosmology?

BALTIMORE – The James Webb Space Telescope lives up to its promise as a way machine. The sensitive observatory of the spectacle found and confirmed more distant galaxies, and therefore existed earlier in the history of the universe, than any seen before.

The telescope, which is also known as JWST, has confirmed the extreme distances to four galaxies, one of which sets a record for cosmic distance by brightness about 13.475 billion years ago, astronomers reported on December 12 at the First Science Proceedings from the JWST conference. A dozen other galaxies can be spotted just 550 million years or less after the Big Bang, indicating that light from those galaxies reached the telescope at least 13.1 billion years ago.

Taken together, the new observations suggest that galaxies formed earlier and faster than previously thought. “We are entering a new era,” says astronomer Swara Ravindranath of the Space Telescope Science Institute in Baltimore.

That new age is thanks in part to JWST’s ability to see far infrared light (SN: 10/6/21). For ultimate things, like the first stars and galaxies, their visible light is concentrated by the immense expansion of the universe into the longer infrared wavelengths, which are invisible to the human eye and some distance ahead of telescopes. But now, measurements that were previously impossible are suddenly easy with JWST, researchers say.

“JWST is the most powerful infrared telescope ever built,” astrophysicist Jane Rigby said at the conference. Rigby, NASA’s Goddard Space Flight Center in Greenbelt, Md., is where JWST’s observational operations are based. “Almost across the board, the science is better than expected.”

Also in the first image, released in July, astronomers spotted galaxies whose light originated 13 billion years ago or more (SN: 7/11/22). But those distances were estimates. To measure distances precisely, astronomers need spectra, measurements of how much light galaxies emit at many wavelengths. Those measurements are slower and more difficult than making pictures.

“Thanks to this glorious telescope, we now get spectra … for hundreds of galaxies at once,” said Emma Curtis-Lake, an astronomer at the University of Hertfordshire in England.

Among those are four of the earliest galaxies ever seen, some of which are less than 400 million years after the Big Bang, Curtis-Lake and colleagues reported at the meeting and published in a December 8 arXiv.org paper. The team spotted these record holders in a patch of sky that the Hubble Space Telescope once swept through the most distant galaxies (SN: 1/3/10).

The previous distance record holder existed between 13.3 billion and 13.4 billion years ago, or about 400 million years after the Big Bang (SN: 1/28/20). JWST confirmed the distance to that galaxy and returned with three more, whose light came from the beginning at 325 million years after the Big Bang.

galaxies are also surprisingly primitive, chemically speaking, lacking the heavier elements hydrogen and helium.

“We don’t see it in today’s universe,” said Ravindranath, who was not involved in the new discovery. It could mean that not many of the stars in the galaxy died in supernova explosions, which spread heavy elements around the universe, suggesting that the original star galaxies were not very large.

In another part of the sky, JWST detected 26 galaxies that may have existed about 550 million years or earlier after the Big Bang, astronomer Steven Finkelstein and colleagues reported at the meeting and published a paper Nov. 10 at arXiv.org.

“The emotion, the visceral level, looking at these images is amazing,” said Finkelstein, of the University of Texas at Austin.

The first of these discoveries, called the Maisie Finkelstein Daughter Galaxy, appears to be just 380 million years after the Big Bang, researchers reported in December. Literary Journal of Astrophysics. The longest galaxies in the survey lie together as much as 130 million years before Maisie. Those distant galaxies still need to be confirmed with spectral work, but the team is expected to obtain that information in the next few weeks.

And the distant galaxies that lie behind a large galaxy cluster called Abell 2744 are even more numerous and distant than expected, astrophysicist Guido Roberts-Borsani of UCLA said at the meeting.

Before JWST observed the cluster, astronomers predicted that galaxies from 13.2 billion years ago should effectively be found. “But we found two,” said Roberts-Borsani, who reported the results at the meeting. “So it’s a little weird.” It could mean galaxies are forming earlier and faster than thought, he said, although it could also mean JWST is looking at a unique galaxy-rich sky fullness.

All these new galaxies are excited because they could be responsible for making the universe transparent to visible light, a process astronomers call reionization.SN: 12/2/22). Before the first stars ignited, the universe was filled with a thick soup of particles. The first stars and galaxies were flooding the universe in ultraviolet light, stripping electrons from hydrogen atoms and allowing the light to zip all the way to JWST.

The new data, Roberts-Borsani said, “give us constraints on when this process started, ended, and which galaxies were responsible for this process.”