The galaxies in today’s universe have come a long way since the first structures that appeared after the Big Bang. Today, galaxies like our Milky Way are made up of hundreds of billions of stars, but that wasn’t always the case.
Currently, researchers using NASA james webb space telescope (JWST) has been looking deep into the history of the universe, just 700 million years after the birth of Earth. big bangoccurred about 13.8 billion years ago. They studied infant galaxies from that era to see how star formation differed from that of galaxies at the time. universe today.
of galaxy It was observed as part of the JWST Advanced Extragalactic Exploration (JADES) cooperation and was seen to be actively forming. star. Interestingly, this early galaxy had a very dense core with a concentration of stars similar to galaxies in the modern universe (which are made up of about 1,000 times as many stars) .
However, astronomers have noticed that star formation is occurring farther away from the center, and that formation activity gradually increases toward the outside of the galaxy as the galaxy grows in size. Astronomers had previously used theoretical models to predict this “inside-out” star growth dynamics in galaxies from this era, and now they have obtained observations that support that hypothesis.
Related: James Webb Space Telescope (JWST) — The Complete Guide
“One of the many reasons why Webb was such a game-changer for us astronomers is that it allowed us to observe things that were previously predicted through modeling,” said study co-author and university faculty member. said William Baker, a doctoral student in the Bendish Institute. This was said in a paper published in Cambridge, England. statement.
“It’s like being able to check your homework.”
Using Webb’s data, the researchers were able to estimate the ratio of young to old stars, which they translated into average star mass and formation rate.
Modeling of stellar populations reveals old stars at the center of galaxies. However, the surrounding disk of gas and dust was undergoing extremely active star formation, with the mass of stars on the outskirts doubling every 10 million years or so. The newborn star may then move towards the center of the galaxy, much like an ice skater stretching out his arms to spin faster.
“Therefore, we speculate that two scenarios are possible for building this core. The first is continued inside-out growth, where initial disk formation occurs within a very compact disk. , forming the nucleus currently observed,” the authors explained. of paperpublished online today (October 11) in the journal Nature Astronomy.
“Another idea is that the disk that first formed experienced an influx of gas into the center due to compression (perhaps caused by instability caused by the clump, which then formed the core. Then the disk (are re-formed by the deposition of new gases),” they added.
Sandro Tacchera, lead author of the study, said the team would like to observe more galaxies from the same time period in the early universe to see if they share these star formation dynamics. are. By studying galaxies over time, astronomers can gain a deeper understanding of how galaxies grow and evolve into the bustling giant galaxies we see today. You can do it.
