Have you ever had a heavy metal phase during your teenage years? If so, then you might have something in common with “teenage” galaxies, which are also into heavy metal – nickel. This surprising discovery is just one of many made among galaxies that formed within the first 3 billion years after the Big Bang.
The research team combined the light spectra of 23 out of 33 teenage galaxies observed last summer to create a composite picture of a typical young galaxy. This composite image led to the discovery of some shared compositional insights, with the presence of eight elements being detected: hydrogen, helium, nitrogen, oxygen, silicon, sulfur, argon, and nickel.
Lead author Allison Strom from Northwestern University expressed her astonishment, saying, “Never in my wildest dreams did I imagine we would see nickel. Even in nearby galaxies, people don’t observe this. There has to be enough of an element present in a galaxy and the right conditions to observe it. No one ever talks about observing nickel. Elements have to be glowing in gas in order for us to see them. So, in order for us to see nickel, there may be something unique about the stars within the galaxies.”
However, it wasn’t just the presence of nickel that was unusual. These teenage galaxies tend to be at higher temperatures, with hot pockets reaching over 13,350 degrees Celsius (24,062 degrees Fahrenheit), significantly higher than galaxies in the current universe, which are about 9,700 degrees Celsius (17,492 degrees Fahrenheit).
“These teenage years are really important because that’s when the most growth happens,” Strom said. “By studying this, we can begin exploring the physics that caused the Milky Way to look like the Milky Way – and why it might look different from its neighboring galaxies.”
The observations were made by JWST as part of the CECILIA (Chemical Evolution Constrained using Ionized Lines in Interstellar Aurorae) Survey, in honor of Cecilia Payne-Gaposchkin, one of the first women to earn a PhD in Astrophysics. Her research allowed humanity to understand the elements present in stars and galaxies.
Gwen Rudie, a staff scientist at Carnegie Observatories, further explained, “Allison and I recognize that our own work revealing the chemistry of these very early galaxies is built upon her legacy.”
The study has been published in The Astrophysical Journal Letters.
