FAST Telescope Spots Starless Hydrogen Cloud That May Be a 'Dark Galaxy'

· Science · China

Astronomers using China's FAST radio telescope have discovered a compact cloud of hydrogen with no visible stars or galaxy around it, which could be one of the strongest candidates yet for an isolated 'dark galaxy.' The cloud contains nearly 500,000 times the sun's mass in neutral hydrogen, according to the discovery paper, which was posted as a preprint. Dark galaxies are hypothetical objects whose gas has not condensed into stars, and candidates are rare and hard to confirm. The finding adds to a small set of systems that could test ideas about how galaxies form and why some gas clouds fail to ignite star formation. The work relies on FAST's sensitivity to faint radio emission from neutral hydrogen. Independent follow-up will be needed to confirm the cloud's nature and distance.

Why it matters：Candidate dark galaxies are rare probes of star formation and galaxy assembly, and a detection with the mass reported here would give theorists a concrete case to test why some gas never turns into stars.

Key points

  • FAST, China's radio telescope, made the detection.
  • The cloud holds nearly 500,000 solar masses of neutral hydrogen.
  • The paper was posted as a preprint.

Sources (original reporting)

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