The identified potential black holes were observed with the NuSTAR X-ray space observatory to look for radiation from the hottest gas near the black hole.
Notes on verification
Multiple independent, high-quality sources (NASA, JPL, Caltech NuSTAR site) corroborate the claim verbatim, along with independent science media coverage. [tier=gold indep_score=0.938 clusters=4 claim_tier=notable | framework convergence=single on NASA/JPL official press release on the Boorman et al. 2025 study combining IRAS and NuSTAR data (upstreams: NASA/JPL press release (Boorman et al. 2025 study), IRAS archival data, NuSTAR observations) — publishers independent, evidence may not be | kind=empirical eligibility=high]
Sources
- A third of black holes in the Universe could be hiding from view | BBC Sky at Night Magazine (seed:space_and_astronomy)
- https://www.jpl.nasa.gov/news/how-many-black-holes-are-hiding-nasa-study-homes-in-on-answer/ (corroboration)
- https://nustar.caltech.edu/news/nustar250113 (corroboration)
- https://www.nasa.gov/missions/nustar/how-many-black-holes-are-hiding-nasa-study-homes-in-on-answer/ (corroboration)
- https://scitechdaily.com/nasa-unveils-a-hidden-universe-of-supermassive-black-holes/ (corroboration)
- https://www.space.com/the-universe/black-holes/astronomers-find-hundreds-of-hidden-black-holes-and-there-may-be-billions-or-even-trillions-more (corroboration)