# A Hundred and Nine Flashes

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Text version: https://stenobird.com/podcast/astronomy-daily-space-news-updates-5658676/a-hundred-and-nine-flashes.md
Podcast: [Astronomy Daily: Latest Space News](https://stenobird.com/podcast/astronomy-daily-space-news-updates-5658676)
Published: 2026-09-10T11:43:06+00:00
Episode link: https://www.astronomydaily.io
Audio file: https://dts.podtrac.com/redirect.mp3/mgln.ai/track/op3.dev/e/api.spreaker.com/download/episode/75048228/a_hundred_and_nine_flashes.mp3
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JSON: https://stenobird.com/v1/public/podcasts/astronomy-daily-space-news-updates-5658676/episodes/a-hundred-and-nine-flashes
Duration seconds: 1691

## Resource

Today's episode — S05E190, Thursday September 10, 2026: Main story: 109 fast radio bursts have been used to measure how much galactic feedback has smoothed out the matter in the universe. A fast radio burst lasts about a millisecond, and on its way to us it is dispersed — low radio frequencies slowed more than high ones by free electrons along the path, exactly the way a prism separates white light. The size of that delay counts the ordinary matter the burst passed through. Writing in Nature Astronomy on 8 September, a team led by Kritti Sharma at Caltech, with Vikram Ravi, Liam Connor and Elisabeth Krause (University of Arizona), used 109 bursts localised to host galaxies out to redshift ~0.3 — most of them from Caltech's DSA-110 — to constrain the suppression of matter clustering by feedback, and the gas fractions of groups and clusters between 10^13 and 10^15 solar masses. They find more gas retained than the X-ray picture implies: gas fractions about 1.9σ above stacked eROSITA measurements, and slightly above the Atacama Cosmology Telescope's kSZ constraints, consistent with the bursts counting cool gas that X-rays miss. The constraint is already competitive with both of those far larger experiments, cutting the uncertainty on clustering at these scales by roughly a factor of eight. That matters because feedback is the confound sitting under the S8 tension — it mimics the signature of massive neutrinos and of some dark energy and dark matter models. The technique's foundation is Australian: the Macquart relation, established with ASKAP in Western Australia in 2020, is what found the universe's missing ordinary matter in the first place. The rest of the news: · Hypersoft X-ray sources: NASA and the Chandra X-ray Center announced a new class of object on 9 September…

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