REVIEW 7 cited by
HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
Signed reviews
read the original abstract
Recently, the Hydrogen Epoch of Reionization Array (HERA) collaboration has produced the experiment's first upper limits on the power spectrum of 21-cm fluctuations at z~8 and 10. Here, we use several independent theoretical models to infer constraints on the intergalactic medium (IGM) and galaxies during the epoch of reionization (EoR) from these limits. We find that the IGM must have been heated above the adiabatic cooling threshold by z~8, independent of uncertainties about the IGM ionization state and the nature of the radio background. Combining HERA limits with galaxy and EoR observations constrains the spin temperature of the z~8 neutral IGM to 27 K < T_S < 630 K (2.3 K < T_S < 640 K) at 68% (95%) confidence. They therefore also place a lower bound on X-ray heating, a previously unconstrained aspects of early galaxies. For example, if the CMB dominates the z~8 radio background, the new HERA limits imply that the first galaxies produced X-rays more efficiently than local ones (with soft band X-ray luminosities per star formation rate constrained to L_X/SFR = { 10^40.2, 10^41.9 } erg/s/(M_sun/yr) at 68% confidence), consistent with expectations of X-ray binaries in low-metallicity environments. The z~10 limits require even earlier heating if dark-matter interactions (e.g., through millicharges) cool down the hydrogen gas. Using a model in which an extra radio background is produced by galaxies, we rule out (at 95% confidence) the combination of high radio and low X-ray luminosities of L_{r,\nu}/SFR > 3.9 x 10^24 W/Hz/(M_sun/yr) and L_X/SFR<10^40 erg/s/(M_sun/yr). The new HERA upper limits neither support nor disfavor a cosmological interpretation of the recent EDGES detection. The analysis framework described here provides a foundation for the interpretation of future HERA results.
Forward citations
Cited by 7 Pith papers
-
Impact of numerical stability in Bayesian noise wave calibration on global 21-cm experiments
Near-collinearity of noise-source and load design-matrix columns makes REACH’s five-parameter Bayesian calibration non-reproducible; a four-parameter Chebyshev fit with hot-load T_NS(ν) recovery and spike masking stab...
-
CosmoUiT: A Vision Transformer-UNet Hybrid for Fast and Accurate Emulation of 21-cm Maps from the Epoch of Reionization
A Vision Transformer-UNet hybrid emulates 3D EoR 21-cm cubes conditioned on reionization parameters, matching simulated large-scale power spectra with mild small-scale suppression.
-
A New Boundary Condition on Reionization
A zero-lag Pearson correlation between 21-cm and line-intensity maps is predicted to drop sharply at ionized fractions of 1-10%, providing a novel marker for the onset of reionization.
-
Joint 21-cm and CMB Forecasts for Constraining Self-Interacting Massive Neutrinos
21-cm power spectrum forecasts show HERA and CMB-S4 combined can constrain the neutrino self-coupling G_eff to about 10 percent across strong, moderate, and mild interaction models, with futuristic lunar arrays reachi...
-
Prospects for measuring neutrino mass with 21-cm forest
Using an analytic halo model, the authors forecast that 21-cm forest observations with SKA-LOW could constrain the total neutrino mass to about 0.1 eV, potentially distinguishing neutrino mass hierarchies.
-
Probing initial isocurvature perturbation with 21cm one-point statistics
A Fisher forecast from 21cmFAST simulations shows 21cm variance can constrain the CDM isocurvature fraction to about 3e-4 with SKA, while skewness is an order of magnitude weaker.
-
Simulation-based inference on warm dark matter from HERA forecasts
Using neural ratio estimation on mock HERA power spectra, the authors forecast 95% lower bounds on the thermal WDM mass that exceed the 5.3 keV Lyman-alpha limit when the galaxy threshold mass Mturn is below 1e8 M_sun.
Discussion (0). Continue with ORCID to comment.