AWhat changed
HERA analyzed 94 selected nights of Phase I observations and reported 95% upper limits on the dimensionless 21 cm brightness-temperature fluctuation power of 457 mK² at redshift 7.9 and wave number 0.34 h/Mpc, and 3,496 mK² at redshift 10.4 and 0.36 h/Mpc. The analysis also explored implications for astrophysical heating under specified models.
Scientific scope
HERA analyzed 94 selected nights of Phase I observations and reported 95% upper limits on the dimensionless 21 cm brightness-temperature fluctuation power of 457 mK² at redshift 7.9 and wave number 0.34 h/Mpc, and 3,496 mK² at redshift 10.4 and 0.36 h/Mpc. The analysis also explored implications for astrophysical heating under specified models. These are upper limits, not a positive detection of the 21 cm power spectrum. The 94 nights include the earlier 18-night sample; they are not independent observations for counting purposes. Foreground avoidance, calibration, crosstalk mitigation and estimated signal-loss corrections affect the result. Heating and reionization implications depend on model families, priors and external data; the power-spectrum upper limits and model-specific Bayesian credible limits are distinct. This interferometric fluctuation measurement is not the global-sky spectrum measured by EDGES or SARAS.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. These are upper limits, not a positive detection of the 21 cm power spectrum. The 94 nights include the earlier 18-night sample; they are not independent observations for counting purposes. Foreground avoidance, calibration, crosstalk mitigation and estimated signal-loss corrections affect the result. Heating and reionization implications depend on model families, priors and external data; the power-spectrum upper limits and model-specific Bayesian credible limits are distinct. This interferometric fluctuation measurement is not the global-sky spectrum measured by EDGES or SARAS.
Contributors
- The named authors in the research record · SCIENCE: These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.
Provisional WRS assessment, edition 2026-10-28.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.
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