Astronomers using NASA/ESA/CSA’s James Webb Space Telescope have discovered a typical extremely metal-poor, star-forming, blue, compact dwarf galaxy in the constellation Ursa Major, I. Zwicki 18 (abbreviated). I took a stunning image of I Zw 18).
This web image shows I Zwicky 18, a blue, compact dwarf galaxy about 59 million light-years away in the constellation Ursa Major. I Zwicky 18’s nearby companion galaxy can be seen at the bottom of the image. This companion star may be interacting with the dwarf galaxy and may have triggered the galaxy’s recent star formation. Image credits: NASA / ESA / CSA / Webb / Hirschauer other.
I Zw 18 It is located approximately 59 million light years away in the constellation Ursa Major.
This galaxy, also known as Mrk 116, LEDA 27182, and UGCA 166, discovered It was discovered in the 1930s by Swiss astronomer Fritz Zwicky.
At only 3,000 light years in diameter, it is much smaller than our own Milky Way galaxy.
I Zw 18 has experienced several bursts of star formation and has two large starburst regions at its center.
The wispy brown filaments surrounding the central starburst region are bubbles of gas heated by stellar winds and intense ultraviolet light emitted by hot, young stars.
“Metal-poor star-forming dwarf galaxies in the local universe are close analogs of high-redshift dwarf galaxies,” said Dr. Alec Hirschauer of the Space Telescope Science Institute and colleagues.
“Because the history of enrichment of a particular system tracks the accumulation of heavy elements through successive generations of stellar nucleosynthesis, low-abundance galaxies are likely to be more likely to be affected by a common phenomenon in the early Universe, including the global epoch of peak star formation. It mimics the astrophysical conditions where most of the cosmic star formation and chemical enrichment is expected to have taken place.”
“Thus, at the lowest metallicities, we may be able to approximate the star-forming environment of the time just after the Big Bang.”
“I Zw 18 is one of the most metal-poor systems known, with a measured gas-phase oxygen abundance of only about 3% of solar power production,” the researchers said. added.
“At a distance of 59 million light-years and with global star formation rate values measured at 0.13 to 0.17 solar masses per year, this laboratory is designed to support young stars in an environment similar to the one in which they were discovered. It’s an ideal laboratory for studying both the demographics and the demographics of stars that evolved in the very early days of the universe.”
Dr. Hirschauer and his co-authors used Webb to study the life cycle of I Zw 18 dust.
“Until now, it was thought that the first generation of stars began forming only recently, but the NASA/ESA Hubble Space Telescope found “The dimmer and older red stars in the galaxy suggest that their formation began at least 1 billion years ago, and possibly 10 billion years ago,” the researchers said.
“Therefore, this galaxy may have formed at the same time as most other galaxies.”
“New observations by Webb reveal the detection of a set of dust-covered evolved star candidates. They also provide details about Zw 18’s two main star-forming regions. To do.”
“Webb’s new data suggests that major bursts of star formation in these regions occurred at different times.”
“The strongest starburst activity is now thought to have occurred more recently in the northwestern lobe of the galaxy compared to the southeastern lobe.”
“This is based on the relative abundance of young and old stars found in each lobe.”
of findings will be published in astronomy magazine.
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Alec S. Hirschauer other. 2024. Imaging I Zw 18 with JWST: I. Strategy and first results for dusty stellar populations. A.J., in press. arXiv: 2403.06980
Source: www.sci.news
