114 fast radio bursts measure how galaxies smooth out matter
Dispersion measures from 114 fast radio bursts constrained how strongly energy from galaxies pushes gas out of halos and suppresses matter clustering. The Nature Astronomy paper and Caltech release say the method can help separate galactic feedback from cosmological signals, while the current sample remains most sensitive to massive halos at low redshift.
Science··Morning
The bursts weighed intervening gas
Fast radio bursts are millisecond flashes of radio light from distant galaxies. Their frequencies arrive at different times according to how much ionized gas the signal crosses on its way to Earth. The researchers used dispersion measures and host-galaxy redshifts for 114 bursts to infer spatial fluctuations in that intervening gas. The peer-reviewed Nature Astronomy paper and Caltech's research release describe the same method and central result: the bursts provide an independent observational channel for tracing hard-to-see baryonic matter.[1], [2]
Feedback resembles a cosmological signal
Exploding stars and feeding black holes transfer energy into galactic surroundings and push gas out of halos. This feedback reduces matter clustering on small scales, where neutrino mass, dark matter and dark energy can also leave signatures. Using the burst data, the team constrained how much feedback suppresses the matter power spectrum. The constraints are competitive with legacy measurements from the Atacama Cosmology Telescope and eROSITA, although the different observations do not sample identical scales and halos.[1]
The 114 bursts set an initial constraint
The sample provides a strong starting point but does not represent the full sky. The paper says the bursts are especially sensitive to massive groups and clusters at low redshift. The inference also depends on modelling the gas contribution from each host galaxy. Larger, well-localized samples can narrow that uncertainty; for now, the result turns feedback from an entangled nuisance into a measurable component rather than determining cosmological parameters on its own.[1]
