Researchers have just found an unexpected galaxy using the James Webb Space Telescope (JWST). The large vortex of stars is known as a spiral galaxy of grand design, and its exceptionally old age could change what is known about galaxy formation.
In general, the older a galaxy is, the further away it is from us. Scientists can measure the age and distance of galaxies through something called them redshift – a phenomenon that occurs when light shifts to lower frequencies, redder wavelengths as it crosses large areas of space. This happens for a number of reasons; first, because the universe is expandingOlder stars naturally end up further away. And second, because red is the longest wavelength in the visible spectrum of light, stars that are very far away appear redder and have a higher redshift. JWST is designed to look deep into the red and infrared spectrum, allowing it to see old, distant galaxies clearer than any previous telescope.
But spiral galaxies are generally on the younger side, making the newly discovered galaxy, named A2744-GDSp-z4, an outlier. Galaxies of grand design, such as A2744-GDSp-z4, are characterized by their two well-defined spiral arms. Very few have been found with a redshift above 3.0 – meaning their light has been traveling for almost 11.5 billion years, according to the Las Cumbres Observatory
The newly discovered galaxy, meanwhile, has a redshift of 4.03, meaning the light detected by JWST was emitted more than 12 billion years ago. According to the researchers who discovered it, this means that A2744-GDSp-z4 formed when the universe was only about 1.5 billion years old – and that it appears to have formed very quickly. Considering the estimated value star formation In just a few hundred million years, it has built up a mass of about 10 billion solar masses.
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This goes against the way scientists think spiral galaxies usually form.
“The rarity of high-redshift spirals could be a consequence of the fact that galaxies were dynamically hot at those early epochs,” say the researchers led by Rashi Jain at the National Center for Radio Astrophysics in India, wrote in the new study. “Dynamically hot systems tend to form clumpy structures,” rather than highly ordered spirals, the researchers added.
The team theorizes that the formation of A2744-GDSp-z4 may have been caused by the presence of a stellar bar – gaseous structures found in most galaxies that fuel the birth of stars and gas between the inner and outer regions of a galaxy channeling, which contributes to the formation of galaxies. size and shape of the galaxy. The ancient spiral could also have been formed by the merger of two smaller galaxies, although this seems less likely given its orderly structure, the researchers wrote.
The findings were published December 9 in the preprint database arXiv. The research has not yet been peer-reviewed.
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