Evidence continues to gather that dwarf galaxies played a greater role in shaping the early universe than previously thought.
Astronomers who analyzed James Webb Space Telescope (JWST) data discovered a group of small energy galaxies that could be key players in clearing the universe fog that surrounds the universe after the Big Bang.
Isak Wold, an assistant research scientist at the Catholic University in Washington, DC, told reporters at the 246th American Astronomical Association conference in Alaska. “These small but many galaxies can produce all the light needed to reionize.”
About 380,000 years after the Big Bang, the universe was cooled enough for charged particles to bond to neutral hydrogen atoms, creating a thick, light-sucking mist, an era known as the Dark Age of the Universe. Hundreds of millions of years later, at the birth of the first stars and galaxies, their intense ultraviolet (UV) radiation began to reionize this primitive hydrogen. The process gradually removed the thick mist, allowing the starlight to move freely through space, allowing for the first time to illuminate the universe.
For decades, astronomers have debated what caused this dramatic transformation. Key candidates included large galaxies, black holes mounted quasars, and small low-mass galaxies. New data from JWST now point to the smallest candidates, suggesting that these small galaxies act like a space flashlight illuminating the early universe.
To identify these early galaxies, Wold and his colleagues focused on a huge galaxy cluster called Abell 2744 or Pandora’s Cluster, about four billion light years away from the constellation sculptor. The enormous gravity of this cluster serves as a natural magnifying glass, bending and amplifying the light coming from the much further ancient galaxy behind it. Coupled with the powerful instruments of the JWST, researchers peered into this natural habit, nearly 13 billion years ago.
Using JWST’s near-infrared camera (NIRCAM) and near-infrared spectrometer (NIRSPEC), the team searched for specific green emission lines from double-ionized oxygen, which is characteristic of intense star formation. This light was originally emitted in the visible range, but was extended into infrared light as it traveled through the expanding universe. NASA Statement.
The search gave us 83 small Starburst galaxies when the universe was only 800 million years old and about 6% of its current age.
“Our analysis […] They existed in sufficient numbers and show they packed enough ultraviolet rays to promote renovations to this universe,” Waldo said in a statement.
Today, similar primitive galaxies such as the so-called “Green Pea” galaxies are rare, but are known to emit approximately 25% of the ionized ultraviolet rays into the surrounding space. If the early galaxies worked the same way, Wald said they produced enough light to regenerate the hydrogen fog and make the universe transparent.
“When it comes to producing ultraviolet rays, these small galaxies will weigh far more than they weigh,” he said in a statement.
