Fast radio bursts, or FRBs, are intense and brief blasts of cosmic radio waves that carry the physical fingerprints of matter distributed across the universe, according to new research published on Tuesday (Sept. 8) in the journal Nature Astronomy. As these signals travel billions of light-years to reach Earth, they pass through dense clouds of gas and dust in galaxies, allowing astronomers to directly measure the large-scale distribution of ordinary matter and test theories regarding dark matter, dark energy, and the mass of neutrinos.
Mapping the Universe With Fast Radio Bursts
Ordinary matter accounts for just around 5% of the universe’s energy/matter budget, while the remaining 95% is composed of dark energy (68%) and dark matter (27%). Vikram Ravi, a professor of astronomy at the California Institute of Technology (Caltech), and graduate student Kritti Sharma analyzed a sample of about 100 FRBs to study how matter clusters in the large-scale regions between galaxies.
“We’ve established that FRBs are a leading probe of the distribution of matter in the universe,” Kritti Sharma said in a statement. “These FRB data can be used to enhance cosmology experiments that are trying to answer questions about dark matter, dark energy, and the mass of neutrinos.”
Did you know? While astronomers have discovered about 85 since 2007, upcoming radio telescopes are expected to detect tens of thousands of these signals in the coming years.
Measuring Galactic Feedback Effects
To accurately map cosmic structures, researchers must account for astrophysical processes that smooth out clumpiness in the universe. Energy pumped out from the hearts of galaxies by feeding supermassive black holes acts as a feedback mechanism that thins surrounding gas and redistributes matter across vast distances.
“The feedback process thins the gas around the galaxies, redistributing matter across vast distances. It smooths out clumps of matter in a way that looks astonishingly similar to what massive neutrinos do, or what dark energy or dark matter theories predict,” Ravi said. “Unless scientists can independently measure this contribution from feedback, they can’t tell these effects apart.”
Researchers have evaluated galactic feedback and its influence on matter’s clumpiness across vast intergalactic expanses for the very first time by analyzing FRBs in this novel study. The research team found that while galactic feedback suppresses surrounding material and makes it less clumpy, the effect is weaker than has previously been measured.
“Our analysis of FRBs reveals how gas ejected by astrophysical feedback suppresses cosmic structure,” team member Elisabeth Krause of the University of Arizona said in the statement. “This is amazing considering we only had about 100 FRBs in our sample. It’s only the beginning.”
The Future of FRB Cosmology Research
Cosmological studies utilizing FRBs are poised to receive a significant advancement once Nevada hosts the operational launch of Caltech’s Deep Synoptic Array (DSA) in the year 2029. Discovering tens of thousands of FRBs with this high-powered radio telescope will represent a tremendous advantage for cosmological science.
Frequently Asked Questions
What causes fast radio bursts?
Magnetars—defined as rapidly spinning dead stellar remnants possessing the most intense magnetic fields found anywhere in the cosmos—are widely believed by researchers to be the origin of FRBs.
How do FRBs help scientists study dark matter?
During their multibillion-light-year journey toward Earth, FRBs make their way through thick pockets of galactic gas and dust. This “cosmic fog” changes the original FRB signal. What this means is these blasts of radio waves carry the fingerprints of how matter in the universe is distributed.Mapping the distribution and structural clustering of ordinary matter within galaxies provides researchers with a useful tool for tracking dark matter dispersion, neutrino masses, and dark energy influences.
When will new FRB data become available on a large scale?
Caltech’s Deep Synoptic Array (DSA) begins operating in 2029 in Nevada and is expected to find tens of thousands of FRBs.
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