James Webb Space Telescope Feed Post

Pristine Gas Clump Near GN-z11

Webb may have found evidence for the long-theorized first generation of stars — as well as the most distant active supermassive black hole to date. GN-z11, a galaxy that existed 430 million years after the big bang, is giving up its secrets. This extremely bright galaxy was discovered by @NASAHubble and is one of the earliest distant galaxies ever observed. Webb found the first clear evidence explaining why it is so luminous: a 2-million-solar-mass central supermassive black hole rapidly gobbling up matter. Observers using Webb also discovered a pocket of pristine gas in the galaxy’s halo. Theory and models both suggest that clumps of helium like these may collapse to form Population III stars, the first generation of stars in the early universe. These stars have never been observed. They’d be made almost entirely of hydrogen and helium (unlike modern stars, which contain heavier elements) and be massive, bright, and hot. Finding them is one of the most important goals of modern astrophysics. Learn more: science.nasa.gov/missions/webb/webb-unlocks-secrets-of-on... Credit: NASA, ESA, CSA, Ralf Crawford (STScI) This image: This two-part graphic shows evidence of a gaseous clump of helium in the halo surrounding galaxy GN-z11. In the top portion, at the far right, a small box identifies GN-z11 in a field of galaxies. The middle box shows a zoomed-in image of the galaxy. The box at the far left displays a map of the helium gas in the halo of GN-z11, including a clump that does not appear in the infrared colors shown in the middle panel. In the lower half of the graphic, a spectrum shows the distinct “fingerprint” of helium in the halo. The full spectrum shows no evidence of other elements and so suggests that the helium clump must be fairly pristine, made of hydrogen and helium gas left over from the big bang, without much contamination from heavier elements produced by stars. Theory and simulations in the vicinity of particularly massive galaxies from these epochs predict that there should be pockets of pristine gas surviving in the halo, and these may collapse and form Population III star clusters. Image description: A graphic labeled “Galaxy GN-z11, Pristine Gas Clump Near GN-z11.” The graphic is divided into two sections. The top half of the graphic features a rectangular image of a field of galaxies. At lower right, a small region is highlighted with a white box. A white arrow extends leftward to a larger box showing an enlarged view of the highlighted area. The box is labeled “GN-z11” and features a fuzzy yellow dot at lower right. A second arrow extends left to a white box labeled “Helium Two Detected.” It shows a pixelated image with a dark purple background. Two yellow-green blobs with red contours are at lower right and upper left. The bottom half of the graphic shows a single line graph with a white jagged line of data plotting the relative brightness of the second clump in the helium two image at different wavelengths of light. A red shaded area at about 1.90 microns marks the position of a helium 2 emission line. Image & Description by NASA