| 1st of June 2020 |
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| Finding Residual Baryons with Fast Radio Bursts |
| by Macquart et al. |
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It is thought the Universe is made up of
~68% dark energy, ~27% dark matter, ~5% normal matter.
While dark energy and dark matter are mysteries, normal
"baryonic" matter is well known to us. However, astronomers
had only been able to find evidence for about half
the normal matter predicted to exist,
as most of baryonic content of the Universe
is in a very diffuse state that is difficult to detect.
Macquart et al. last week reported the detection of this missing matter, based on observations of Fast Radio Bursts (FRBs) detected with ASKAP. The ASKAP Commensal Real-time ASKAP Fast Transients (CRAFT) survey team developed a mode capable of localizing FRBs with sufficient accuracy to identify their host galaxies. Follow-up observations with optical telescopes enabled the redshifts, and hence distances, to the galaxies to measured. Comparison with the Dispersion Measure of the FRBs -- the spread in frequency of the burst, which depends upon the density of matter between the FRB and the Earth -- allowed the missing matter to be detected for the first time. The results are published in the journal Nature. |