Researchers analyzing a sample of about 100 fast radio bursts have directly measured how galactic feedback thins gas and suppresses cosmic structure. Detailed by Space and UA.News, the findings reveal that while supermassive black holes smooth matter across vast distances, their effect is weaker than previously measured.
Probing the Dark Universe Through Cosmic Fog
Fast radio bursts are brief, intense blasts of radio waves that scientists now associate with magnetars, which are rapidly rotating dead stars possessing the universe’s strongest magnetic fields. As these signals travel billions of light-years across the cosmos to reach Earth, they pass through dense clouds of gas and dust scattered throughout galaxies. According to Space, this cosmic fog alters the original signal, meaning that the incoming radio waves carry detailed fingerprints of how matter is distributed throughout the universe.
Ordinary matter accounts for roughly 5% of the universe’s total energy and matter budget, while the remaining 95% is made up of dark energy at 68% and dark matter at 27%. Within that 5% slice of ordinary matter, the second most abundant particles after photons are neutrinos. Because these particles interact with other matter so infrequently that roughly 100 trillion of them pass through a human body every second, they earned the nickname ghost particles.
Accurately measuring neutrino mass, alongside understanding dark matter and dark energy, remains a central goal for modern cosmology.
Measuring the Impact of Galactic Feedback
To trace the distribution of dark matter and neutrinos by mapping ordinary matter, researchers must first account for other forces that smooth out cosmic clumpiness. Chief among these is astrophysical feedback, which involves energy pumped out from the centers of galaxies by feeding supermassive black holes. UA.News notes that this process thins the surrounding gas and redistributes it across large distances, making matter less inhomogeneous.
The analytical challenge lies in the fact that this feedback smooths out matter clumps in a way that closely mimics the theoretical effects of massive neutrinos, dark energy, or dark matter models. Without an independent way to measure feedback, scientists cannot easily separate these overlapping phenomena. Analyzing a sample of roughly 100 fast radio bursts allowed researchers to directly measure this feedback impact for the very first time.
“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.”
Vikram Ravi, professor of astronomy at the California Institute of Technology
What the Data Reveals About Cosmic Structure
The investigation showed that galactic feedback indeed smooths surrounding material and suppresses cosmic structure, but that smoothing effect is demonstrably weaker than prior measurements had suggested.
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,
said Kritti Sharma, a graduate student and team leader working with Vikram Ravi at the California Institute of Technology.
Looking Ahead to the Deep Synoptic Array
Elisabeth Krause of the University of Arizona observed that extracting these findings from a sample of only 100 bursts demonstrates the immense potential of the method.
“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.”
Elisabeth Krause, University of Arizona team member
The pace of discovery is expected to accelerate dramatically in 2029, when Caltech’s Deep Synoptic Array begins operating in Nevada. While astronomers have discovered about 85 fast radio bursts since 2007, the upcoming facility is projected to detect tens of thousands of these signals, providing researchers with an unprecedented dataset to map the invisible architecture of the universe.
