Mysterious fast radio bursts could reveal hidden matter around galaxies
Rapid bursts of radio waves that originate millions to billions of light years away from Earth could be used as probes to investigate halos of difficult-to-see diffuse gas surrounding nearby galaxies. New research shows that these pulses, called fast radio bursts (FRBs), slow as they pass through the gas enveloping the galaxies between their source and Earth. This also has the effect of dispersing their radio frequencies. Researchers from Caltech found twice as much material as previously believed in these envelopes that enshroud galaxies. This has implications for how these collections of stars and planets evolve over time.
The astronomers looked at 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 travelled to Earth unimpeded. Thus, this effect can be used to probe 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,” Tolman Postdoctoral Scholar Research Associate in Astronomy at Caltech, Liam Connor, said in a statement. ”
Astronomers have found that there is more matter in gas haloes than previously believed. “These gaseous reservoirs are enormous,” Connor said. “If the human eye could see the spherical halo that surrounds the nearby Andromeda galaxy, the halo would appear one thousand times larger than the Moon.”