Overview

• Researchers measured dispersion in signals from 69 fast radio bursts to estimate the density of diffuse gas along their paths.
• About 76% of ordinary matter resides in the intergalactic medium, with 15% in galaxy halos and the remainder inside stars or cold galactic gas.
• These observations provide the first direct confirmation of advanced cosmological simulations predicting how baryonic matter is distributed.
• Caltech’s DSA-110 array, Australia’s ASKAP and optical telescopes at Palomar and Keck were used to localize bursts and determine their distances.
• Next-generation arrays like DSA-2000 are expected to detect thousands of FRBs annually, enabling a detailed map of the cosmic web and new insights into galaxy evolution.