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Constraining primordial black holes as dark matter using the global 21-cm signal with X-ray heating and excess radio background

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arxiv 2107.02190 v2 pith:IHWXSO4R submitted 2021-07-05 astro-ph.CO astro-ph.HEhep-ph

classification astro-ph.COastro-ph.HEhep-ph
keywords heatingconstraintsabsorptiondarkglobalmathrmmatterpbhs
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abstract

Using the global 21-cm signal measurement by the EDGES collaboration, we derive constraints on the fraction of the dark matter that is in the form of primordial black holes (PBHs) with masses in the range $10^{15}$-$10^{17}\,$g. Improving upon previous analyses, we consider the effect of the X-ray heating of the intergalactic medium on these constraints, and also use the full shape of the 21-cm absorption feature in our inference. In order to account for the anomalously deep absorption amplitude, we also consider an excess radio background motivated by LWA1 and ARCADE2 observations. Because the heating rate induced by PBH evaporation evolves slowly, the data favour a scenario in which PBH-induced heating is accompanied by X-ray heating. Also, for the same reason, using the full measurement across the EDGES observation band yields much stronger constraints on PBHs than just the redshift of absorption. We find that 21-cm observations exclude $f_{\mathrm{PBH}} \gtrsim 10^{-9.7}$ at 95% CL for $M_{\mathrm{PBH}}=10^{15}\,$g. This limit weakens approximately as $M_{\mathrm{PBH}}^4$ towards higher masses, thus providing the strongest constraints on ultralight evaporating PBHs as dark matter over the entire mass range $10^{15}$-$10^{17}\,$g. Under the assumption of a simple spherical gravitational collapse based on the Press-Schechter formalism, we also derive bounds on the curvature power spectrum at extremely small scales ($k\sim 10^{15}\,$Mpc$^{-1}$). This highlights the usefulness of global 21-cm measurements, including non-detections, across wide frequency bands for probing exotic physical processes.

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Cited by 6 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Primordial black holes as cosmic accelerators of light dark matter: Novel direct detection constraints

    hep-ph 2026-02 unverdicted novelty 7.0 of 10

    Primordial black hole evaporation generates light fermionic dark matter capable of producing electron recoils in XENONnT, LZ, and PandaX-4T, enabling new constraints on DM-electron interactions after including Earth a...

  2. Impact of numerical stability in Bayesian noise wave calibration on global 21-cm experiments

    astro-ph.CO 2026-07 conditional novelty 6.0 of 10

    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...

  3. Primordial Black Hole from Tensor-induced Density Fluctuation: First-order Phase Transitions and Domain Walls

    astro-ph.CO 2026-05 unverdicted novelty 6.0 of 10

    Tensor perturbations from FOPT and domain-wall sources are claimed to induce second-order scalar perturbations large enough to form primordial black holes, potentially all of the dark matter.

  4. Complementary Probes of Warped Extra Dimension: Colliders, Gravitational Waves and Primordial Black Holes from Phase Transitions

    hep-ph 2025-02 conditional novelty 6.0 of 10

    In Randall-Sundrum warped extra dimension models, the supercooled radion phase transition can form primordial black holes that account for all of dark matter for IR scales 10 TeV to 10^4 TeV, with correlated gravitati...

  5. The Irrelevance of Primordial Black Hole Clustering in the LVK mass range

    astro-ph.CO 2025-02 accept novelty 6.0 of 10

    Initial spatial clustering of primordial black holes is irrelevant for binary mergers in the LVK mass range because FIRAS spectral-distortion constraints limit the clustering scale to below the merger-relevant separat...

  6. Anisotropic Neutrino Emission from Spinning, Moving, and Charged Primordial Black Holes

    astro-ph.CO 2025-08 reject novelty 4.0 of 10

    Kerr-Newman black holes moving relativistically emit neutrinos in a narrow forward cone, a combination of known spin and Doppler effects.

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