Astronomers Capture Faint Hydrogen Signal, Paving Way for Vast Cosmic Maps
Using South Africa's MeerKAT array, astronomers have directly detected an extremely weak radio emission from neutral hydrogen billions of light-years away, showcasing a new approach for mapping the Universe on massive scales.
Researchers from the University of Manchester and the University of the Western Cape have directly observed a faint 21-centimeter radio signal emitted by neutral hydrogen that has traveled four to five billion years to reach Earth. Analyzing roughly 96 hours of observations from South Africa's MeerKAT array, they identified the hydrogen intensity-mapping signal from two distinct periods in cosmic history, proving the method can map vast regions by measuring the collective emission of many galaxies.
The study, appearing in The Astrophysical Journal Letters, highlights the technique's potential to replace traditional galaxy-by-galaxy surveys, offering a faster route to three-dimensional cosmological maps. Lead author Sourabh Paul called the result a "very exciting milestone," noting the difficulty of isolating the signal from foreground noise and interference. Co-authors emphasized that the data, taken when MeerKAT was newly operational, suggest a rich archive for future work and foreshadow the role of the upcoming Square Kilometre Array Observatory.
Why it matters
It validates a fast, large-scale method to chart cosmic structure, aiding research on galaxy evolution and dark matter.
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