The deeper we look into space, the further back in time we look. Light from some of the youngest galaxies in our universe must travel billions of years to reach us, where it is captured by our information-rich instruments from the cosmic dawn. This light can tell us not only where we came from, but where we might be headed.
To understand the evolution of many of these early, “teenage” galaxies, a team of astrophysicists led by Northwestern University examined data from the James Webb Space Telescope (JWST), which looked at worlds that formed only two to three. Billions of years after the Big Bang.
The observations raised some interesting surprises.
Specifically, the team analyzed the results of the Chemical Evolution Constrained Using Ion Lines in Interstellar Aurora (CECILIA) survey to find that not only do these galaxies appear hotter than expected, but they also appear to contain heavy elements, such as nickel.
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The researchers focused on 33 distant galaxies for 30 continuous hours. They then combined the wavelengths of light collected from 23 of those galaxies to create a composite picture of what’s happening in these structures — these spectra contain clues regarding things like average temperatures and the elements that may be lurking within them.
“This erases the details of individual galaxies but gives us a better sense of an average galaxy. It also allows us to see faint features,” said Alison Strom, lead author of the study and an assistant professor of physics and astronomy at Northwestern University. In the current situation.
The composite picture of galaxies contains eight identifiable elements: hydrogen, helium, nitrogen, oxygen, silicon, sulfur, argon, and nickel. While lighter elements were expected, the presence of nickel, which is heavier than iron in the periodic table, came as somewhat of a surprise.
“Never in my wildest dreams did I imagine we would see nickel,” Strom said.
Even in ancient and nearby galaxies, nickel is rarely observed, after multiple star life cycles, which means multiple rounds of supernovae, allowing heavier elements to accumulate and spread throughout the galaxy.
“Nobody ever talks about observing nickel,” Strom said. “The elements have to glow in the gas for us to be able to see them. So, for us to be able to see nickel, there may be something unique about stars within galaxies.”
Strom believes that the high temperatures observed in these early galaxies may be related to their strange chemical composition in some way: “Ultimately, the fact that we see a higher characteristic temperature is just another manifestation of the different chemical DNA, because the temperature and chemistry of the gas in the galaxies are related to intrinsically linked.”
It was the study published November 20 in The Astrophysical Journal Letters.