AZ Daily Star: How U of A research is helping find the origins of the Milky Way, universe
NASA’s SPHEREx observatory is oriented in a horizontal position, revealing all three layers of photon shields as well as the telescope. This photo was taken at BAE Systems in Boulder, Colorado, in April 2024.
NASA/JPL-Caltech/BAE Systems
A two-year NASA mission is using research from a University of Arizona team to discover the origins of the Milky Way and the universe.
SPHEREx, or Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer, is a space telescope that launched on March 11 and will survey the entire sky every six months with infrared light to create a 3-D map.
Researchers hope to discover what happened immediately after the Big Bang, when the universe expanded in a fraction of a second.
“We want to measure as precisely as possible the imprints of inflation,” said Elisabeth Krause, the UA team lead for this project and associate professor of astronomy and physics.
By measuring this inflation they can explore the structure of the universe as never done before, she said.
The earliest detection of the universe is called the Cosmic Microwave Background, which is recorded light from approximately 400,000 years after the Big Bang.
If successful, SPHEREx could collect data from the first billionth of a trillionth of a trillionth of a second, according to NASA.
Another team member is Tim Eifler, an associate professor of astronomy and physics.
He said that inflation was just a theory from a long time ago, but SPHEREx is the first time that a mission is dedicated to constraining it, making it more defined and explored.
The current models of the universe’s foundations are riddled with issues and inconsistencies like predicting the universe to be very flat, which would be extremely unlikely. But the cosmic inflation theory could find the solution to these problems.
“This very early crafted theory is quite beautiful in explaining these problems that we see in the universe, but it’s never been tested, so it will be tested for the first time,” Eifler said.
The mission will produce a data set, cataloging hundreds of millions of galaxies and stars in 102 infrared colors.
The project team is part of the UA-based Arizona Cosmology Lab, which researches the composition and evolution of the universe.
A former UA post-doctoral student, Yosuke Kobayashi, developed a mathematical model to create a more concise catalog and theoretical calculations.
Annie Moore, a current PhD student in her final year, is using this model and testing it with synthetic data and seeing, in simulated analyses, how certain parameters and sensitivity affect final results before using it on the data from SPHEREx.
“This is the first time that I’ve ever really worked on something where I’m trying to answer a question that no one has before,” Moore said.
Another PhD student, Joe Adamo, is using machine-learning and artificial intelligence to create a software which streamlines the use of Kobayashi’s model, which will work hand in hand with Moore’s research to help create a comprehensive catalog using summary statistics.
“We’re all very motivated to have this mission be successful,” Adamo said.
The UA team collaborates with researchers from other universities and groups, including the California Institute of Technology.
Krause said this project is over ten years in the making as her first email about the project was from 2013. They, with colleagues from around the world, endured several rounds of proposals and estimations of success to get NASA funding and an official mission launch.
SPHEREx will also explore the concept of dark matter and detect life-sustaining molecules like water and carbon dioxide.
Dark matter has a strong gravitational pull and allows for the formation of galaxies from the clumping of objects in space.
“So, where there over densities in large scale distribution of dark matter, we will find more galaxies,” Krause said. “So, what we measure from the SPHEREx data is the number of galaxy pairs as a function of separation.”
By finding the distance between galaxies, they can discover imprints of inflation from early universe expansion like never done before.
The space telescope is currently and will remain in low Earth orbit. But technology allows it to record objects farther out and into different galaxies, scanning an approximate 40,000 square degrees, the entire sky.
“That’s something that we have only been able to do with very large error bars before,” Krause said, referring to how SPHEREx is a dedicated mission to scanning the sky. “So now we get a factor ten magnifying glass on that question.”
It is cooling down from the launch and is it is too hot to produce any data right now. But Adamo said it should start taking data within the next month.
Once the data starts coming in, the UA team will begin analysis.
“SPHEREx is not only great in going after the early universe physics of inflation, but also interesting in understanding structure growth in the universe,” Eifler said.