New research shows that these pulses, called fast radio bursts (FRBs), slow as they pass through the gas surrounding the galaxies between their source and Earth. This also results in the dispersion of their radio frequencies. Using this to probe galactic gas halos, researchers from the California Institute of Technology (Caltech) found twice as much material as previously thought in these envelopes surrounding galaxies. This has implications for how these collections of stars and planets evolve over long periods of time. Astronomers examined a sample of 474 distant FRBs with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) confirming that 24 FRBs intercepted by galactic halos were indeed slowed down compared to others that traveled to Earth unobstructed. Thus, this result can be used to detect the material through which the FRB passes. “Our study shows that FRBs can act as skewers of all the matter between our radio telescopes and the source of the radio waves,” said Tolman Postdoctoral Scholar Research Associate in Astronomy at Caltech, Liam Connor. statement (opens in a new tab). “We have used fast radio bursts to shine a light through the halos of galaxies near our Milky Way and measure their hidden material.” Using more distant FRBs outside our galaxy to probe the vast reservoirs of gas surrounding other galaxies has already revealed a surprise. Astronomers have discovered that there is more matter in gaseous haloes than previously thought, about twice as much as predicted by theoretical models. “Those gas tanks are huge,” Connor said. “If the human eye could see the globular halo surrounding the nearby Andromeda Galaxy, the halo would appear a thousand times larger than the moon.” Why these halo gas are the remnants of the same material used to form stars and planets, a deeper investigation of them could lead to a better understanding of how galaxies evolve over periods of billions of years.
An artist’s illustration shows the 300,000 light-year wide halo of gas surrounding the Milky Way. (Image: NASA/CXC/M.Weiss; NASA/CXC/Ohio State/A.Gupta et al.) Although researchers are currently unsure of the origin of FRBs, first detected in 2007, they believe that these pulses of electromagnetic radiation lasting from a fraction of a millisecond to a few milliseconds are emitted by rapidly rotating magnetic dead stars called magnets. Evidence of this connection was presented in 2020 when Caltech’s Survey for Transient Astronomical Radio Emission 2 (STARE2) instrument teamed up with CHIME to detect a massive FRB explodes into the Milky Way. Since their discovery in 2007, hundreds of FRBs have been observed, and these revelations are expected to keep rolling in thanks, in part, to Caltech’s 110 plate Deep Synoptic Array (opens in new tab) or DSA-110. The project has already detected several FRBs and traced them to the galaxies from which they originated. Caltech scientists have plans to build an even larger telescope array in the coming years, which will consist of 2,000 dishes. Named DSA-2000, the project will be the most powerful radio observatory ever built and will be able to detect and identify thousands of FRBs and their sources each year. “This is just the beginning,” said Caltech assistant professor of astronomy Vikram Ravi. “As we discover more FRBs, our techniques can be applied to study individual haloes of different sizes and in different environments, addressing the unsolved problem of how matter is distributed in the universe.” The team’s research was published (opens in a new tab) in the journal Nature Astronomy. Follow us on Twitter @Spacedotcom or up Facebook.
