Astronomers using the NASA/ESA/CSA James Webb Space Telescope have discovered at least five young globular clusters within SPT 0615-JD1 (also known as the Cosmic Gems Arc), a strongly lensed galaxy that existed when the universe was 460 million years old.
These images show the galaxy cluster SPT-CL J0615-5746 (right) and part of this cluster (left), showing two clearly lensed galaxies. The Cosmic Gems arc is shown along with several galaxy clusters. Images courtesy of NASA / ESA / CSA / Webb / L. Bradley, STScI / A. Adamo, Stockholm University / Cosmic Spring Collaboration.
“These galaxies are thought to be the main source of intense radiation that reionized the early universe,” said Dr Angela Adamo, astronomer at Stockholm University and the Oskar Klein Centre.
“What’s special about the Cosmic Gems Ark is that thanks to gravitational lensing, we can actually resolve galaxies down to the parsec scale.”
SPT 0615-JD1 was originally discovered in Hubble Space Telescope images obtained by the RELICS (Reionizing Lensing Cluster Survey) program of the lensing galaxy cluster SPT-CL J0615-5746, located about 7.7 billion light-years away in the constellation of Scorpio.
The Webb telescope will enable Dr Adamo and his colleagues to see where stars are forming and how they are distributed, in a similar way that the Hubble telescope is used to study the local galaxy.
Webb’s observations provide a unique opportunity to study star formation and the internal structure of young galaxies at unprecedented distances.
“The combination of the Webb Telescope’s incredible sensitivity and angular resolution at near-infrared wavelengths, along with gravitational lensing by a large foreground galaxy cluster, made this discovery possible that would not have been possible with any other telescope,” said Dr. Larry Bradley, an astronomer at the Space Telescope Science Institute.
“The surprise and excitement I felt when I first opened the Webb images was overwhelming,” Dr. Adamo said.
“We saw a string of tiny bright dots projected from one side to the other. These cosmic gems are star clusters.”
“Without Webb, we would never have known we were observing star clusters in such a young galaxy.”
Astronomers say the discovery connects different scientific disciplines.
“These results provide direct evidence of the formation of protoglobular clusters in faint galaxies during periods of reionization and help us understand how these galaxies successfully reionized the Universe,” Dr Adamo said.
“This discovery also places important constraints on the formation of globular clusters and their early properties.”
“For example, the high stellar densities found in galaxy clusters provide the first indications of processes occurring within them and give new insights into the possible formation of very massive stars and black hole seeds that are important for the evolution of galaxies.”
In the future, the team hopes to construct a sample of galaxies that can achieve a similar resolution.
“I am convinced that there are more such systems in the early universe waiting to be discovered, which will improve our understanding of early galaxies even further,” said Dr Eros Vanzella, astronomer at the Bologna Observatory for Astrophysics and Space Sciences (INAF).
of Investigation result Published in today’s journal Nature.
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A. Adamo othersA bound star cluster observed in a lensed galaxy 460 million years after the Big Bang. NaturePublished online June 24, 2024, doi: 10.1038/s41586-024-07703-7
Source: www.sci.news
