Northwestern University-led team analyzes first results from the CECILIA Survey using NASA’s James Webb Space Telescope (JWST) to study chemistry of distant “teenage galaxies.
In a surprising discovery, astrophysicists at Northwestern University have found that “teenage galaxies” formed billions of years ago contain unexpected elements, including nickel and oxygen, which are notoriously difficult to observe. The research, conducted as part of the Chemical Evolution Constrained using Ionized Lines in Interstellar Aurorae (CECILIA) Survey, utilizes data from NASA’s James Webb Space Telescope (JWST) to gain insights into the chemistry and evolution of galaxies. These findings shed light on the growth and transformation of galaxies over the course of cosmic history.
Insights Into Galactic Evolution:
The CECILIA Survey aims to understand how galaxies grew and changed over the 14 billion years since the Big Bang. By targeting “teenage galaxies” that formed two-to-three billion years after the Big Bang, the researchers hope to uncover the experiences that shaped their trajectories into adulthood. Northwestern’s Allison Strom, the lead researcher, likens a galaxy’s spectra to its “chemical DNA.” By examining this DNA during a galaxy’s formative years, scientists can better understand how it grew and how it will evolve into a more mature galaxy. This knowledge is crucial in unraveling the mysteries of why some galaxies appear “red and dead” while others, like our Milky Way, are still actively forming stars.
‘Chemical DNA’ Insight Into Galaxy Formation:
The CECILIA Survey, named after astronomer Cecilia Payne-Gaposchkin, observes the spectra of distant galaxies. By analyzing the spectra, researchers can identify key elements present in a galaxy, such as oxygen and sulfur, which provide insights into its past and future activities. The teenage years of a galaxy are particularly important, as this is when the most significant growth occurs. The researchers hope to explore the physics that shaped the Milky Way and understand why it differs from neighboring galaxies.
Spectra Surprises:
During the initial phase of the CECILIA Survey, the team used the JWST to observe 33 distant teenage galaxies for a continuous 30 hours. From this data, they constructed a composite picture by combining the spectra from 23 of these galaxies. The ultra-deep spectrum revealed the presence of eight distinct elements, including hydrogen, helium, nitrogen, oxygen, silicon, sulfur, argon, and nickel. The unexpected observation of nickel, a rare and difficult-to-detect element, surprised the researchers. The study also found that the teenage galaxies were unusually hot, with temperatures exceeding 13,350 degrees Celsius (24,062 degrees Fahrenheit).
Conclusion:
The early results from the CECILIA Survey using the JWST have provided valuable insights into the chemistry and evolution of teenage galaxies. The unexpected presence of nickel and the unusually high temperatures observed in these galaxies challenge our current understanding of galactic formation and evolution. Further studies from the CECILIA Survey will shed more light on the complex processes that shape galaxies throughout the universe’s history. By unraveling the mysteries of these teenage galaxies, scientists hope to gain a deeper understanding of our own Milky Way and its place in the cosmos.
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