Estimates of ordinary matter in the universe exceed the amount observed in stars and galaxies, leaving much of it unaccounted for. Researchers from the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/Fast Radio Bursts Collaboration, including McGill University and MIT, have developed a new method to seek out this "missing" matter by combining galaxy locations with fast radio burst detections. A fast radio burst, or FRB, is an ultrabright, millisecond flash of radio waves emitted by extremely energetic phenomena in the distant universe.
The new method revealed not only whether missing matter was present, but also its location: specifically, in diffuse clouds surrounding galaxies and galaxy groups. The analysis also showed that the missing matter is spread over a much larger region than predicted by simulations, extending roughly four million light-years from galaxies.
"Fast radio bursts are amazingly effective in probing the distribution of matter in the universe," said Victoria Kaspi , study co-author and Professor of Physics at McGill University. The research was led by Haochen Wang, a graduate student in MIT's Kavli Institute for Astrophysics and Space Research, and Kiyoshi Masui, Associate Professor of Physics at MIT.
The researchers said the findings support the idea that matter is flung outside galaxies by black hole jets, exploding stars and other energetic processes, and suggest those processes are more powerful than previously thought.
"By mapping the shape of missing matter, we can understand how galaxies form and how they interact with their environment," Wang said.
More than 2,500 signals analyzed
The team used data from two sources: the CHIME radio telescope near Penticton, B.C., and the Dark Energy Spectroscopic Instrument (DESI) in Tucson. CHIME detects incoming radio waves, including fast radio bursts, while DESI measures incoming light from over 30 million galaxies to study the puzzle of "dark energy."
From CHIME's catalogue of detections, members of the CHIME/FRB Collaboration analyzed 2,870 FRB signals. As fast radio bursts travel through space, their signals become increasingly smeared by the matter they pass through. The researchers measured this effect and compared it with galaxy locations across the universe to determine how much of the matter was associated with galaxies and how much was diffuse matter surrounding them.
The team said these results demonstrate that fast radio bursts can be a reliable method by which to search for missing matter. As CHIME continues to detect more FRBs, they noted, this method can only improve.
"We got it to work for the first time and will get it to work even more precisely as data gets better," Masui said.
About this study
" Measurement of the Dispersion–Galaxy Cross-Power Spectrum with the Second CHIME/FRB Catalog ," by Haochen Wang (MIT), Kiyoshi Masui (MIT), Victoria Kaspi (McGill) et al., was published in Physical Review Letters.
CHIME and CHIME/FRB are supported by the Canada Foundation for Innovation, the Natural Sciences and Engineering Research Council of Canada, and the provinces of Quebec, British Columbia and Ontario.
The study was supported in part by the U.S. National Science Foundation.
About this release
This press release was developed in collaboration with the Institute Office of Communications at MIT and based on a story by Jennifer Chu .
