An unusual spiral galaxy with two arms has been discovered in the early universe.

In the early stages of the universe's evolution, its inhabitants were primarily "clumpy" and turbulent galaxies, while spiral disks were virtually nonexistent during that epoch. However, using the James Webb Space Telescope, astronomers have, for the first time, observed a massive spiral galaxy with two distinct arms—just 1.5 billion years after the Big Bang.

https://naked-science.ru/article/astronomy/v-rannej-vselennoj-obnaru2024-12-18 10:01:04

Scientists still cannot confidently determine when the first spiral galaxies emerged: only a few such objects have been found at high redshifts (indicating a relatively ancient Universe). It was previously believed that galaxies in the young Universe exhibited a "clumpy" structure due to a hot and turbulent gas environment; however, the results of a new study, accepted for publication in the journal Astronomy & Astrophysics, challenge these established assumptions.

A research team led by Rashi Jain and Yogesh Wadadekar from the National Centre for Radio Astrophysics — Tata Institute of Fundamental Research (India) observed an ancient object named A2744-GDSp-z4 using the James Webb Space Telescope — a relatively large and massive spiral galaxy. The researchers were able to examine its structure in detail thanks to data obtained through the UNCOVER and Medium band Mega Science programs.

The results revealed that the diameter of the "spiral giant" is approximately 10 kiloparsecs (32,600 light-years), and its stellar mass is about 14 billion solar masses. The star formation rate in A2744-GDSp-z4 is also remarkably high (around 58 solar masses per year) and comparable to that of contemporary spiral galaxies. Furthermore, roughly half of the stars in the ancient galaxy formed in just a few hundred million years.

The authors of the study paid special attention to the distribution of light across the galaxy, which appeared as two well-defined spiral arms: in the ultraviolet range, they observed what are referred to as "beads on a string" — chains of regions with active star formation. As they transitioned to longer-wavelength optical ranges, the arms became smoother and resembled classical spiral structures.

The analysis also revealed the presence of ionized gas, which stimulates active star formation. Specifically, in one of the southern regions of the disk, they detected particularly intense emission, indicating a powerful stellar "nursery."

The discovery of A2744-GDSp-z4 calls into question the understanding of inhabitants of the early Universe and challenges established models of galaxy formation. Further observations will help clarify how exactly the galaxy formed its large elongated disk with a diameter of about 32,600 light-years and when the spiral arms emerged. For comparison, the visible part of the Milky Way's disk measures approximately 100,000 light-years.