Madrid, June 6 (Europa Press) –
Webb Space Telescope observations identify galaxies in most distant and early universe They shine with lots of hot young stars.
These are shown in the result 242nd Meeting of the American Astronomical Societyin Albuquerque, New Mexico.
Ryan Endsley of the University of Texas at Austin led the research on the galaxies. They existed between 500 and 850 million years after the Big Bang.
This was a pivotal moment known as the Epoch of Reionization. Hundreds of millions of years after the Big Bang, the universe was shrouded in a gaseous fog that made it opaque to energetic light. A billion years after the Big Bang, the fog lifted and the universe became transparent, a process known as reionization. Scientists debate whether there are active supermassive black holes or galaxies filled with hot, young stars The main reason for reionization was
as part of the program ZES (Advanced Deep Extragalactic Survey) — A major in Webb’s first year of science — Endsley and his colleagues studied these galaxies with Webb’s NIRSpec (Near-Infrared Spectrograph) instrument to search for signs of star formation and found them in abundance Can go
“Nearly all of the galaxies we find show unusually strong emission line signatures that indicate recent intense star formation. These first galaxies were very good at forming hot, massive stars.endsley said this is a statement from NASA.
These massive, bright stars emitted streams of ultraviolet light, which turned the surrounding gas from opaque to transparent by ionizing atoms, removing electrons from their nuclei. Because these early galaxies contained such large populations of hot, massive stars, they may have been the main drivers of the reionization process. The subsequent recombination of electrons and nuclei gives rise to characteristically strong emission lines.
Endsley and his colleagues also found evidence that these young galaxies experienced periods of rapid star formation, which were accompanied by quiet periods that formed fewer stars. These fits and starts can occur when galaxies have captured clumps of the gaseous raw material needed to form stars. Alternatively, as massive stars explode rapidly, they may have periodically injected energy into the surrounding atmosphere, Preventing gas from condensing to form new stars.
Another element of the JADES program involves searching for the first galaxies that existed when the universe was less than 400 million years old. By studying these galaxies, astronomers can figure out how star formation was different in the first few years after the Big Bang than it is today. Light from distant galaxies is stretched to longer wavelengths and redder colors by the expansion of the universe, a phenomenon called redshift. By measuring a galaxy’s redshift, astronomers can tell how far away it is, and therefore when it existed in the early universe. Before Webb, only a few dozen galaxies had been observed above a redshift of 8, when the universe was less than 650 million years old, But JADES has now discovered about a thousand of these very distant galaxies.
The gold standard for determining redshift is by looking at a galaxy’s spectrum, which measures its luminosity at a myriad of adjacent wavelengths. But a good approximation can be determined by taking photographs of a galaxy using filters covering a narrow band of colors to obtain a handful of brightness measurements. In this way, researchers can estimate the distances of many thousands of galaxies at a time.
Kevin Hanlein of the University of Arizona in Tucson and his colleagues used Webb’s NIRCam (Near Infrared Camera) instrument to obtain these measurements, called photometric redshifts, and identified more than 700 candidate galaxies that then existed when the universe was between 370 million and 650 million years old. Year. The sheer number of these galaxies far exceeded predictions from observations made prior to Webb’s launch. The resolution and sensitivity of the observatory is allowing astronomers to see these distant galaxies better than ever before.
“Previously, the first galaxies we could see looked like little blobs. And yet those blobs represent millions or even billions of stars in the beginning of the universe,” Hanlein said. “Now, we can see that some of them are actually elongated objects with visible structure. We can see clusters of stars being born a few hundred million years after the beginning of time.”
