Astronomers discover metal-rich galaxies in the early universe

While analyzing data from the first images of a well-known early galaxy taken by NASA’s James Webb Space Telescope (JWST), Cornell University astronomers found a companion galaxy previously hidden behind the galaxy’s first light. flat, one that seems to already have its own. It has hosted multiple generations of stars despite its young age, estimated at 1.4 billion years.

“We found that this galaxy is chemically abundant, something none of us expected,” said Pu Bing, an astronomy doctoral student who led the data analysis. “JWST changes the way we view this system and opens up new avenues for studying how stars and galaxies formed in the early universe.”

Peng is lead author of “Dusty, Chemically Mature Companion Discovery of the z~4 Starburst Galaxy in JWST Early Release Science Data,” published in Astrophysical Journal Letters.

Previous images captured by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile contained complementary cues that were clearly resolved by JSWT, but could not be interpreted as more than random noise, said Amit Vishwas, a Cornell Center research associate. Center for Astrophysics and Planetary Sciences (CCAPS) and second author of the article.

The team estimated that the companion galaxy, which they named SPT0418-SE, was within 5 kiloparsecs of SPT0418-47, one of the brightest dusty, star-forming galaxies in the early Universe, its distant light doubled and magnified by the gravity of a foreground galaxy. A circle called Einstein’s ring. The Magellanic Clouds, satellites of the Milky Way, are about 50 kiloparsecs away. The proximity indicates that these galaxies must have been interacting with each other and possibly also merging, an observation that adds to the understanding of how early galaxies evolved into larger galaxies.

Las dos galaxias tienen una masa modesta en comparación con las galaxias del universo primitivo, con el «SE» relativamente más pequeño y menos polvoriento, lo que lo hace parecer más azul que el anillo oscuro polvoriento. Basándose en imágenes de galaxias cercanas con colores similares, los investigadores sugieren que pueden vivir «en un halo masivo de materia oscura con vecinos aún no descubiertos».

What was most surprising about the companion galaxy, given its age and mass, was that it was mature metallic: amounts of elements heavier than helium and hydrogen, such as carbon, oxygen, and nitrogen. The team estimated that it is comparable to our sun, which is more than 4 billion years old and has inherited most of its minerals from previous generations of stars that took 8 billion years to form.

“We are seeing the remains of at least two generations of stars that lived and died during the first billion years of the universe’s existence, which we don’t normally see,” Vishwas said. “We think that the star formation process in these galaxies must have been very efficient and started very early in the universe, particularly to explain the abundance of nitrogen measured relative to oxygen, since this ratio is a reliable measure of how many generations of stars lived and died.