NASA’s James Webb Space Telescope (JWST) has examined a galaxy that formed just 430 million years after the Big Bang.
If scientists are right, this galaxy is one of the oldest in existence and could have been a nursery for ancient Population III stars, a holy grail of modern astronomy.
The galaxy, called GN-z11, has a supermassive black hole at its center that weighs the equivalent of 2 million suns.
Its exceptional brightness comes from all the heavy, hot materials the black hole is absorbing.
This image is from the NIRCam (near-infrared camera) on the James Webb Space Telescope. Shows a part of the GOODS-North galaxy field. At bottom right, a fold-out image highlights the galaxy GN-z11, seen just 430 million years after the Big Bang.
The JWST was launched in 2021 to collect the faintest light from distant stars.
This gives us a glimpse into the early days of the formation of our universe, about 13.8 billion years ago.
Their new discovery suggests that the space telescope is well equipped to deliver on its promises.
The galaxy was first detected in 2015 by the Hubble Space Telescope.
GN-z11 is brighter than other nearby stars and galaxies.
At the time, scientists could say it was exceptional, but the Hubble Space Telescope wasn’t powerful enough to help them explain why.
Part of its brightness, astronomers have now claimed, is due to the galaxy hosting a central supermassive black hole that is two million times the mass of our sun.
It is accreting matter rapidly, which is why the area around the black hole appears exceptionally bright.
GN-z11 is also the most distant supermassive black hole ever described by astronomers.
Galaxy GN-z11, shown in the inset, as first detected in 2015 by the Hubble Space Telescope
“We found extremely dense gas, common in the vicinity of supermassive black holes, accreting gas,” lead scientist Roberto Maiolino, a professor of experimental astrophysics at the University of Cambridge, said in a study. statement.
“These were the first clear signs that GN-z11 hosts a black hole that is devouring matter,” he said.
JWST’s NIRCam (near-infrared camera) located GN-z11 in the GOODS-North galaxy field.
The new JWST images may not appear to have the same level of detail as the 2015 Hubble image, but while Hubble captured ultraviolet light, JWST was able to show infrared light.
Infrared is a type of light with a wavelength almost twice that of ultraviolet. It’s important in this case because there were some clues about GN-z11 that Hubble had missed because they could only be seen in infrared.
NIRCam revealed ionized chemical elements, which are often the signature of supermassive black holes accreting material.
Along with this signature, scientists also observed a strong “wind” blowing from the galaxy at between 800 and 1,000 kilometers per second (about 500 to 600 miles per second).
This is also a typical feature of a supermassive black hole, said study co-author Hannah Übler.
“Webb’s NIRCam (near-infrared camera) has revealed an extended component, which tracks the host galaxy, and a compact central source whose colors are consistent with those of an accretion disk surrounding a black hole,” he said.
Together, these factors explain the GN-z11’s unusual brightness.
Maiolino, Übler and their colleagues published their findings in the journal Nature.
Another team used the telescope’s NIRSpec (near-infrared spectrograph) instrument to detect a mass of helium gas surrounding the galaxy.
“The fact that we don’t see anything other than helium suggests that this group must be quite pristine,” Maiolino said.
“This is something that theory and simulations in the vicinity of particularly massive galaxies of these times expected: that pockets of pristine gas would survive in the halo that could collapse and form Population III star clusters.”
Population III stars were some of the first stars in the universe, composed of helium and hydrogen.
Based on the fact that scientists observed helium and nothing else, they believe they have found one of these holy grails of astronomy.
A small box identifies GN-z11 in a field of galaxies (top right). In the middle you can see it enlarged. The far left frame shows the halo of helium gas around the galaxy, including a clump that cannot be seen in the infrared colors in the middle frame. The graphic at the bottom shows the distinctive light signature of helium and no other element. The scientists concluded that this must mean that the helium mass is a pristine remnant of the Big Bang.
These Population III stars formed around the transition point in the early universe, when it moved from simplistic and disordered to complex and ordered.
Based on its early findings, astronomers have enthusiastically claimed that JWST is revealing details about the early universe that disrupt our understanding of astrophysics.
However, not everyone agrees.
There may be simpler explanations than “everything we know is wrong,” according to a recent study. study.
A team of researchers compared images taken by JWST with similar ones captured by the old Hubble Space Telescope, and concluded that now is not the time to throw away the rules of astrophysics.
Instead, they suggest that the findings from both space telescopes are compatible, as long as scientists are willing to look for conventional explanations.
For example, they suggest that perhaps some yet-to-be-understood conditions in the early universe made the formation of brighter stars possible.