Researchers have discovered a unique ultramicrodwarf galaxy on the outskirts of the Andromeda galaxy thanks to the keen eye of an amateur astronomer who examined Processed by The National Science Foundation's NOIRLab's Community Science and Data Center file data. This dwarf galaxy - Pegasus V - was found to contain very few heavy elements in follow-up observations by professional astronomers using the International Gemini Observatory, a project of NSF NOIRLab, and is likely to be one of the first galaxies. fossil".
The PegASUSV galaxy was discovered as part of a systematic search for the Andromeda dwarf galaxy coordinated by David Martinez-Delgado of the Institute of Astronomy of Andalusia, Spain, when amateur astronomer Giuseppe Donatiello discovered a strange feature in image data from the DESI Heritage Imaging Survey. "stain". The image was captured by the Dark Energy Camera built by the U.S. Department of Energy on the Víctor M. Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO). The data are processed through a community pipeline operated by NOIRLab’s Community Science and Data Center (CSDC).
When astronomers used the larger 8.1-meter Gemini North Telescope and the GMOS instrument for follow-up in-depth observations, they discovered the faint stars of Pegasus V, confirming that it is an ultra-faint dwarf galaxy in the outer reaches of the Andromeda Galaxy.
Observations with the Gemini North telescope revealed that this galaxy appears to be extremely devoid of heavy elements compared to similar dwarf galaxies, meaning it is very old and is likely a "fossil" of the first galaxies in the universe.
"We have discovered an extremely faint galaxy whose stars formed very early in the history of the universe," commented Michelle Collins, an astronomer at the University of Surrey in the UK and lead author of the paper announcing the discovery. "This discovery marks the first time that such a faint galaxy has been discovered around Andromeda using astronomical surveys not specifically designed for the mission."
The faintest galaxies are thought to be the first to form. Fossils," these galactic remnants contain clues about the earliest star formation. While astronomers expect there to be many faint galaxies like Pegasus V in the universe, they haven't found as many as their theory predicts. If the number of faint galaxies is indeed lower than predicted, it would mean serious problems with astronomers' understanding of cosmology and dark matter.
So discovering examples of these faint galaxies is an important job, but also a difficult one. Part of the challenge is that these faint galaxies are very difficult to spot, appearing only as a few sparse stars in vast images of the sky.
Emily Charles, a PhD student at the University of Surrey who was also involved in the research, explained: "The problem with these extremely faint galaxies is that they have very few of the bright stars that we usually use to identify them and measure their distances. "The 8.1-meter mirror in Gemini allowed us to find faint old stars, which allowed us to measure the distance of Pegasus V and determine that its star population is extremely old."
The strong concentration of ancient stars discovered by the research team in Pegasus V suggests that. The object is likely a "fossil" of the first galaxies. Compared to other faint galaxies around Andromeda, it "appears to be uniquely old and metal-poor, suggesting that its star formation did cease very early."
Collins concluded: "We hope that further studies of the chemical properties of Pegasus V will Provides clues to the earliest periods of star formation in the universe. This small fossil galaxy from the early universe may help us understand how galaxies formed and whether our understanding of dark matter is correct. "The publicly accessible Gemini North telescope provides a range of capabilities for community astronomers," said Martin Still,
National Science Foundation Gemini Program Officer. In this case, Gemini supported this international team to confirm the existence of the dwarf galaxy, physically correlate it with the Andromeda Galaxy, and determine the metal-deficient nature of its evolving stellar population. "
Upcoming astronomical facilities will bring even more light to faint galaxies.Pegasus V bears witness to a period in the history of the universe known as reionization, and other objects dating back to this period will soon be observed by NASA's James Webb Space Telescope. Astronomers also hope to discover other such faint galaxies in the future using the Vera C. Rubin Observatory, a project of the National Science Foundation's NOIRLab. The Vera C. Rubin Observatory will conduct an unprecedented, 10-year survey of the optical sky called the Legacy Survey of Space and Time (LSST).
