pith. sign in

arxiv: 2605.22161 · v2 · pith:STJ3GBWVnew · submitted 2026-05-21 · 🌌 astro-ph.CO · astro-ph.GA· hep-ph

Blue-tilted Runnings and the JWST Early Galaxy Tension

Mikage U. Kobayashi , Gen Chiaki , Kazutaka Kimura , Kazuyuki Akitsu , Kazunori Kohri , Tomo Takahashi , Kazuyuki Omukai This is my paper

Pith reviewed 2026-06-30 16:22 UTC · model grok-4.3

classification 🌌 astro-ph.CO astro-ph.GAhep-ph
keywords JWST early galaxiesblue-tilted spectrumspectral runningprimordial power spectrumCMB constraintsprimordial black holesΛCDM tensionhigh-redshift galaxies
0
0 comments X

The pith

Positive running parameters α_s ≃ 0.02 and β_s ≃ 0.02 in the primordial spectrum resolve the JWST early galaxy tension at 1σ when fitted jointly with CMB data.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper tests whether a blue-tilted spectrum of density perturbations, achieved through positive running of the spectral index, can explain the excess of massive galaxies at high redshifts reported by JWST compared to standard ΛCDM predictions. It shows that specific values of the running parameters allow the enhanced small-scale power to match the observed galaxy abundance while remaining consistent with CMB constraints at the 1σ level. The same spectral tilt is noted as compatible with primordial black hole formation on much smaller scales. This modification targets the shape of the initial fluctuation spectrum rather than introducing new late-time physics.

Core claim

For α_s ≃ 0.02 and β_s ≃ 0.02, a joint analysis with CMB observations shows that the tension can be resolved at the 1σ confidence level. Such a blue-tilted spectrum is also plausible from the perspective of primordial black hole formation on much smaller scales in the early Universe.

What carries the argument

The running parameters α_s and β_s that produce a blue tilt by increasing the amplitude of the primordial power spectrum on small scales.

If this is right

  • The abundance of galaxies with stellar masses around 10^10 solar masses at redshifts 6.5 to 9 matches JWST reports.
  • The model remains compatible with CMB observations inside 1σ confidence.
  • The same parameters permit primordial black hole formation on much smaller scales.
  • The standard ΛCDM prediction for early structure formation is adjusted upward on small scales without changing the overall cosmology.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Probes sensitive to small-scale power, such as pulsar timing or microlensing, could independently test the required blue tilt.
  • The parameters might alter predictions for other early-universe observables like the abundance of minihalos.
  • Inflation models would need to produce a spectral index that increases toward smaller scales to realize these values.

Load-bearing premise

The chosen running parameters produce no conflicts with other datasets or physical requirements beyond the CMB and JWST galaxy counts mentioned in the abstract.

What would settle it

A direct measurement or tighter constraint from future data showing that the running of the spectral index must be near zero or negative on the relevant scales would rule out this resolution.

Figures

Figures reproduced from arXiv: 2605.22161 by Gen Chiaki, Kazunori Kohri, Kazutaka Kimura, Kazuyuki Akitsu, Kazuyuki Omukai, Mikage U. Kobayashi, Tomo Takahashi.

Figure 1
Figure 1. Figure 1: FIG. 1. Halo mass functions (HMFs) with [PITH_FULL_IMAGE:figures/full_fig_p006_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Cumulative stellar mass densities (CSMDs) at redshift [PITH_FULL_IMAGE:figures/full_fig_p007_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Same as Fig. 2 but at redshift [PITH_FULL_IMAGE:figures/full_fig_p008_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Maginalized 1- and 2- [PITH_FULL_IMAGE:figures/full_fig_p010_4.png] view at source ↗
read the original abstract

The recent James Webb Space Telescope (JWST) observations reported the unexpectedly large abundance of massive galaxies with stellar masses of $\sim 10^{10}~M_{\odot}$ at high redshifts $z \simeq 6.5 - 9$ compared with the prediction of the standard $\Lambda$CDM model. As a possible solution to the tension, we consider a blue-tilted spectrum of density perturbations with a positive running. We find that, for $\alpha_s \simeq 0.02$ and $\beta_s \simeq 0.02$, a joint analysis with CMB observations shows that the tension can be resolved at the 1$\sigma$ confidence level. Such a blue-tilted spectrum is also plausible from the perspective of primordial black hole formation on much smaller scales in the early Universe.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The manuscript claims that a blue-tilted primordial power spectrum with positive running parameters α_s ≃ 0.02 and β_s ≃ 0.02 resolves the JWST early-galaxy tension (excess massive galaxies at z ≃ 6.5–9) when jointly analyzed with CMB data at the 1σ level, while remaining plausible for primordial black hole formation on smaller scales.

Significance. If the result holds under full scrutiny, the work supplies a minimal, scale-dependent modification to the primordial spectrum that simultaneously addresses the JWST galaxy counts and permits PBH production, offering a unified early-universe explanation without late-time new physics. The approach is falsifiable via existing and forthcoming intermediate-scale probes.

major comments (2)
  1. [joint analysis (abstract and associated results section)] The central claim that α_s ≃ 0.02 and β_s ≃ 0.02 resolve the tension at 1σ in the joint CMB+JWST analysis is load-bearing; the manuscript must demonstrate that these same parameters leave the matter power spectrum consistent with intermediate-scale observables (Lyman-α forest, galaxy clustering, tSZ clusters) on 1–100 Mpc^{-1}, because the running necessarily alters power across those decades in k. Absence of such checks risks trading the JWST tension for new ones.
  2. [parameter choice and joint-analysis description] The specific numerical values α_s ≃ 0.02 and β_s ≃ 0.02 are presented as the solution that achieves 1σ consistency; the manuscript should report the CMB-only posterior constraints on these running parameters (or the Δχ² penalty when they are fixed to these values) to establish that the chosen point is not already excluded before JWST data are added.
minor comments (1)
  1. Notation for the running parameters (α_s, β_s) should be defined explicitly on first use with reference to the standard expansion of n_s(k) around a pivot scale.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive and detailed report. We address each major comment point-by-point below, providing the strongest honest defense of the manuscript while agreeing to strengthen the presentation where the concerns are valid.

read point-by-point responses

  1. Referee: [joint analysis (abstract and associated results section)] The central claim that α_s ≃ 0.02 and β_s ≃ 0.02 resolve the tension at 1σ in the joint CMB+JWST analysis is load-bearing; the manuscript must demonstrate that these same parameters leave the matter power spectrum consistent with intermediate-scale observables (Lyman-α forest, galaxy clustering, tSZ clusters) on 1–100 Mpc^{-1}, because the running necessarily alters power across those decades in k. Absence of such checks risks trading the JWST tension for new ones.

    Authors: We agree that explicit verification against intermediate-scale probes is necessary to ensure the proposed running does not introduce new tensions. The blue-tilted running with the quoted values primarily boosts power at the very small scales (k ≳ few Mpc^{-1}) relevant to JWST galaxies and PBH formation; the induced change at 1–100 Mpc^{-1} is modest and remains within the broad uncertainties of current Lyman-α, galaxy-clustering, and tSZ data. Nevertheless, to make this transparent, we will add a new subsection (or appendix) in the revised manuscript that shows the linear matter power spectrum for the best-fit running parameters and directly compares it to the relevant observational bounds. revision: yes

  2. Referee: [parameter choice and joint-analysis description] The specific numerical values α_s ≃ 0.02 and β_s ≃ 0.02 are presented as the solution that achieves 1σ consistency; the manuscript should report the CMB-only posterior constraints on these running parameters (or the Δχ² penalty when they are fixed to these values) to establish that the chosen point is not already excluded before JWST data are added.

    Authors: The quoted values were identified from the joint posterior; we will therefore add the requested CMB-only constraints (or the Δχ² penalty relative to the standard ΛCDM run) in the revised results section. This will explicitly show the tension (if any) with CMB data alone and quantify how much the JWST likelihood improves the fit, thereby clarifying that the point is not already ruled out by CMB observations. revision: yes

Circularity Check

0 steps flagged

No significant circularity found

full rationale

The paper proposes positive runnings α_s and β_s as a phenomenological adjustment to the primordial spectrum to address the JWST early galaxy tension. The abstract states that specific values α_s ≃ 0.02 and β_s ≃ 0.02 allow a joint CMB+JWST analysis to resolve the tension at 1σ; this is presented as the direct outcome of their parameter exploration rather than a first-principles derivation or self-referential reduction. No equations or steps are shown that equate a claimed prediction to its own fitted inputs by construction, nor is there load-bearing self-citation, ansatz smuggling, or renaming of known results. The additional remark on PBH plausibility is offered as supporting context, not as the justification for the quoted values. The analysis is therefore self-contained as a standard model-fitting exercise in cosmology.

Axiom & Free-Parameter Ledger

2 free parameters · 1 axioms · 0 invented entities

The central claim rests on the existence of a tension in standard ΛCDM galaxy predictions and the viability of running parameters as free adjustments.

free parameters (2)
  • α_s = ~0.02
    First-order running of spectral index, set to ~0.02 to fit observations.
  • β_s = ~0.02
    Second-order running of spectral index, set to ~0.02 to fit observations.
axioms (1)
  • domain assumption Standard ΛCDM underpredicts the abundance of ~10^10 M_⊙ galaxies at z~6.5-9.
    Baseline assumption establishing the tension to be resolved.

pith-pipeline@v0.9.1-grok · 5699 in / 1135 out tokens · 28908 ms · 2026-06-30T16:22:39.747503+00:00 · methodology

Review history (2 revisions) →

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

53 extracted references · 51 canonical work pages · 27 internal anchors

  1. [1]

    Labb´ eet al., A Population of Red Candidate Massive Galaxies∼600 Myr after the Big Bang, Nature616, 266 (2023), arXiv:2207.12446 [astro-ph.GA]

    I. Labb´ e, P. van Dokkum, E. Nelson, R. Bezanson, K. A. Suess, J. Leja, G. Brammer, K. Whitaker, E. Mathews, M. Stefanon, and B. Wang, A population of red candidate massive galaxies 600 Myr after the Big Bang, Nature616, 266 (2023), arXiv:2207.12446 [astro-ph.GA]

    work page arXiv 2023

  2. [2]

    Boylan-Kolchin, Stress testing ΛCDM with high-redshift galaxy candidates.Nature Astronomy7, 731 (2023), arXiv:2208.01611 [astro-ph.CO]

    M. Boylan-Kolchin, Stress testing ΛCDM with high-redshift galaxy candidates, Nature Astron. 7, 731 (2023), arXiv:2208.01611 [astro-ph.CO]

    work page arXiv 2023

  3. [3]

    C. C. Lovell, I. Harrison, Y. Harikane, S. Tacchella, and S. M. Wilkins, Extreme value statistics of the halo and stellar mass distributions at high redshift: are jwst results in tension with λcdm?, Monthly Notices of the Royal Astronomical Society518, 2511 (2023)

    2023

  4. [4]

    Haslbauer, P

    M. Haslbauer, P. Kroupa, A. H. Zonoozi, and H. Haghi, Has JWST Already Falsified Dark- 12 matter-driven Galaxy Formation?, Astrophys. J. Lett.939, L31 (2022), arXiv:2210.14915 [astro-ph.GA]

    work page arXiv 2022

  5. [5]

    Harikaneet al., Astrophys

    Y. Harikane, M. Ouchi, M. Oguri, Y. Ono, K. Nakajima, Y. Isobe, H. Umeda, K. Mawatari, and Y. Zhang, A Comprehensive Study on Galaxies at z˜ 9-16 Found in the Early JWST Data: UV Luminosity Functions and Cosmic Star-Formation History at the Pre-Reionization Epoch, arXiv preprint arXiv:2208.01612 (2022)

    work page arXiv 2022

  6. [6]

    A redshift-independent efficiency model: star formation and stellar masses in dark matter halos at z>4

    S. Tacchella, S. Bose, C. Conroy, D. J. Eisenstein, and B. D. Johnson, A Redshift-independent Efficiency Model: Star Formation and Stellar Masses in Dark Matter Halos at z≳4, Astrophys. J.868, 92 (2018), arXiv:1806.03299 [astro-ph.GA]

    work page internal anchor Pith review Pith/arXiv arXiv 2018

  7. [7]

    Behrooziet al., The Universe at z>10: predictions forJ W STfrom the universemachine DR1, Mon

    P. Behrooziet al., The Universe at z>10: predictions forJ W STfrom the universemachine DR1, Mon. Not. Roy. Astron. Soc.499, 5702 (2020), arXiv:2007.04988 [astro-ph.GA]

    work page arXiv 2020

  8. [8]

    Parashari and R

    P. Parashari and R. Laha, Primordial power spectrum in light of JWST observations of high redshift galaxies, Mon. Not. Roy. Astron. Soc.526, L63 (2023), arXiv:2305.00999 [astro- ph.CO]

    work page arXiv 2023

  9. [9]

    Early structure forma- tion from primordial density fluctuations with a blue, tilted power spectrum: High-redshift galaxies,

    S. Hirano and N. Yoshida, Early Structure Formation from Primordial Density Fluctuations with a Blue, Tilted Power Spectrum: High-redshift Galaxies, Astrophys. J.963, 2 (2024), arXiv:2306.11993 [astro-ph.GA]

    work page arXiv 2024

  10. [10]

    P. E. Colazo, F. Stasyszyn, and N. Padilla, Structure formation with primordial black holes to alleviate early star formation tension revealed by JWST, Astron. Astrophys.685, L8 (2024), arXiv:2404.13110 [astro-ph.CO]

    work page arXiv 2024

  11. [11]

    D. H. Lyth and E. D. Stewart, More varieties of hybrid inflation, Phys. Rev. D54, 7186 (1996), arXiv:hep-ph/9606412

    work page internal anchor Pith review Pith/arXiv arXiv 1996

  12. [12]

    S. M. Leach, I. J. Grivell, and A. R. Liddle, Black hole constraints on the running mass inflation model, Phys. Rev. D62, 043516 (2000), arXiv:astro-ph/0004296

    work page internal anchor Pith review Pith/arXiv arXiv 2000

  13. [13]

    Black hole formation and slow-roll inflation

    K. Kohri, D. H. Lyth, and A. Melchiorri, Black hole formation and slow-roll inflation, JCAP 04, 038, arXiv:0711.5006 [hep-ph]

    work page internal anchor Pith review Pith/arXiv arXiv

  14. [14]

    Generating Primordial Black Holes Via Hilltop-Type Inflation Models

    L. Alabidi and K. Kohri, Generating Primordial Black Holes Via Hilltop-Type Inflation Mod- els, Phys. Rev. D80, 063511 (2009), arXiv:0906.1398 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2009

  15. [15]

    Running-Mass Inflation Model and Primordial Black Holes

    M. Drees and E. Erfani, Running-Mass Inflation Model and Primordial Black Holes, JCAP 04, 005, arXiv:1102.2340 [hep-ph]

    work page internal anchor Pith review Pith/arXiv arXiv

  16. [16]

    Running Spectral Index from Inflation with Modulations

    T. Kobayashi and F. Takahashi, Running Spectral Index from Inflation with Modulations, 13 JCAP01, 026, arXiv:1011.3988 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv

  17. [17]

    Runnings in the Curvaton

    T. Kobayashi and T. Takahashi, Runnings in the Curvaton, JCAP06, 004, arXiv:1203.3011 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv

  18. [18]

    C. T. Byrnes, P. S. Cole, and S. P. Patil, Steepest growth of the power spectrum and primordial black holes, JCAP06, 028, arXiv:1811.11158 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv

  19. [19]

    Y. S. Furuta, M. Karˇ ciauskas, K. Kohri, and A. S´ aez, Primordial Black Holes as Dark Matter and the Tachyonic Trap During Inflation, arXiv e-prints (2025), arXiv:2511.23182 [astro- ph.CO]

    work page arXiv 2025

  20. [20]

    Kumar and N

    S. Kumar and N. Weiner, Early galaxies from rare inflationary processes and JWST observa- tions, Phys. Rev. D112, 063560 (2025), arXiv:2502.08701 [astro-ph.CO]

    work page arXiv 2025

  21. [21]

    Planck Collaboration, Planck 2018 results. VI. Cosmological parameters, A&A641, A6 (2020), arXiv:1807.06209 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2018

  22. [22]

    More hilltop inflation models

    K. Kohri, C.-M. Lin, and D. H. Lyth, More hilltop inflation models, JCAP12, 004, arXiv:0707.3826 [hep-ph]

    work page internal anchor Pith review Pith/arXiv arXiv

  23. [23]

    Efficient Computation of CMB anisotropies in closed FRW models

    A. Lewis, A. Challinor, and A. Lasenby, Efficient computation of CMB anisotropies in closed FRW models, Astrophys. J.538, 473 (2000), arXiv:astro-ph/9911177

    work page internal anchor Pith review Pith/arXiv arXiv 2000

  24. [24]

    Cosmological parameters from CMB and other data: a Monte-Carlo approach

    A. Lewis and S. Bridle, Cosmological parameters from CMB and other data: A Monte Carlo approach, Phys. Rev. D66, 103511 (2002), arXiv:astro-ph/0205436

    work page internal anchor Pith review Pith/arXiv arXiv 2002

  25. [25]

    Gavas, J

    S. Gavas, J. Bagla, N. Khandai, and G. Kulkarni, Halo mass function in scale invariant models, Mon. Not. Roy. Astron. Soc.521, 5960 (2023), arXiv:2210.17200 [astro-ph.CO]

    work page arXiv 2023

  26. [26]

    T. Abel, G. L. Bryan, and M. L. Norman, The Formation of the First Star in the Universe, Science295, 93 (2002), arXiv:astro-ph/0112088 [astro-ph]

    work page internal anchor Pith review Pith/arXiv arXiv 2002

  27. [27]

    Modeling UV Radiation Feedback from Massive Stars: II. Dispersal of Star-Forming Giant Molecular Clouds by Photoionization and Radiation Pressure

    J.-G. Kim, W.-T. Kim, and E. C. Ostriker, Modeling UV Radiation Feedback from Massive Stars. II. Dispersal of Star-forming Giant Molecular Clouds by Photoionization and Radiation Pressure, ApJ859, 68 (2018), arXiv:1804.04664 [astro-ph.GA]

    work page internal anchor Pith review Pith/arXiv arXiv 2018

  28. [28]

    Fukushima and H

    H. Fukushima and H. Yajima, Radiation hydrodynamics simulations of massive star cluster for- mation in giant molecular clouds, MNRAS506, 5512 (2021), arXiv:2104.10892 [astro-ph.GA]

    work page arXiv 2021

  29. [29]

    M. R. Krumholz, C. F. McKee, and J. Bland-Hawthorn, Star Clusters Across Cosmic Time, ARA&A57, 227 (2019), arXiv:1812.01615 [astro-ph.GA]

    work page arXiv 2019

  30. [30]

    S. Chon, T. Hosokawa, K. Omukai, and R. Schneider, Impact of radiative feedback on the initial mass function of metal-poor stars, MNRAS530, 2453 (2024), arXiv:2312.13339 [astro- 14 ph.GA]

    work page arXiv 2024

  31. [31]

    Gehrels, Confidence Limits for Small Numbers of Events in Astrophysical Data, ApJ303, 336 (1986)

    N. Gehrels, Confidence Limits for Small Numbers of Events in Astrophysical Data, ApJ303, 336 (1986)

    1986

  32. [32]

    The Star Formation Law in Nearby Galaxies on Sub-Kpc Scales

    F. Bigiel, A. Leroy, F. Walter, E. Brinks, W. J. G. de Blok, B. Madore, and M. D. Thorn- ley, The Star Formation Law in Nearby Galaxies on Sub-Kpc Scales, AJ136, 2846 (2008), arXiv:0810.2541 [astro-ph]

    work page internal anchor Pith review Pith/arXiv arXiv 2008

  33. [33]

    R. C. Kennicutt and N. J. Evans, Star Formation in the Milky Way and Nearby Galaxies, ARA&A50, 531 (2012), arXiv:1204.3552 [astro-ph.GA]

    work page internal anchor Pith review Pith/arXiv arXiv 2012

  34. [34]

    B. Carr, K. Kohri, Y. Sendouda, and J. Yokoyama, Constraints on primordial black holes, Rept. Prog. Phys.84, 116902 (2021), arXiv:2002.12778 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2021

  35. [35]

    Direct Detection of Hawking Radiation from Asteroid- Mass Primordial Black Holes,

    A. Coogan, L. Morrison, and S. Profumo, Direct Detection of Hawking Radiation from Asteroid-Mass Primordial Black Holes, Phys. Rev. Lett.126, 171101 (2021), arXiv:2010.04797 [astro-ph.CO]

    work page arXiv 2021

  36. [36]

    Berteaud, F

    J. Berteaud, F. Calore, J. Iguaz, P. D. Serpico, and T. Siegert, Strong constraints on primordial black hole dark matter from 16 years of INTEGRAL/SPI observations, Phys. Rev. D106, 023030 (2022), arXiv:2202.07483 [astro-ph.HE]

    work page arXiv 2022

  37. [37]

    Microlensing constraints on primordial black holes with the Subaru/HSC Andromeda observation

    H. Niikuraet al., Microlensing constraints on primordial black holes with Subaru/HSC An- dromeda observations, Nature Astron.3, 524 (2019), arXiv:1701.02151 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2019

  38. [38]

    Smyth, S

    N. Smyth, S. Profumo, S. English, T. Jeltema, K. McKinnon, and P. Guhathakurta, Updated Constraints on Asteroid-Mass Primordial Black Holes as Dark Matter, Phys. Rev. D101, 063005 (2020), arXiv:1910.01285 [astro-ph.CO]

    work page arXiv 2020

  39. [39]

    Microlensing constraints on Primor- dial Black Hole abundance with Subaru Hyper Suprime-Cam observations of Andromeda,

    S. Sugiyama, M. Takada, N. Yasuda, and N. Tominaga, Microlensing constraints on Primordial Black Hole abundance with Subaru Hyper Suprime-Cam observations of Andromeda, arXiv e-prints (2026), arXiv:2602.05840 [astro-ph.CO]

    work page arXiv 2026

  40. [40]

    Primordial Black Hole Scenario for the Gravitational-Wave Event GW150914

    M. Sasaki, T. Suyama, T. Tanaka, and S. Yokoyama, Primordial Black Hole Scenario for the Gravitational-Wave Event GW150914, Phys. Rev. Lett.117, 061101 (2016), [Erratum: Phys.Rev.Lett. 121, 059901 (2018)], arXiv:1603.08338 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2016

  41. [41]

    Franciolini, V

    G. Franciolini, V. Baibhav, V. De Luca, K. K. Y. Ng, K. W. K. Wong, E. Berti, P. Pani, A. Riotto, and S. Vitale, Searching for a subpopulation of primordial black holes in LIGO- Virgo gravitational-wave data, Phys. Rev. D105, 083526 (2022), arXiv:2105.03349 [gr-qc]

    work page arXiv 2022

  42. [42]

    Andr´ es-Carcasona, A.J

    M. Andr´ es-Carcasona, A. J. Iovino, V. Vaskonen, H. Veerm¨ ae, M. Mart´ ınez, O. Pujol` as, and 15 L. M. Mir, Constraints on primordial black holes from LIGO-Virgo-KAGRA O3 events, Phys. Rev. D110, 023040 (2024), arXiv:2405.05732 [astro-ph.CO]

    work page arXiv 2024

  43. [43]

    Primordial seeds of supermassive black holes

    M. Kawasaki, A. Kusenko, and T. T. Yanagida, Primordial seeds of supermassive black holes, Phys. Lett. B711, 1 (2012), arXiv:1202.3848 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2012

  44. [44]

    Testing scenarios of primordial black holes being the seeds of supermassive black holes by ultracompact minihalos and CMB $\mu$-distortions

    K. Kohri, T. Nakama, and T. Suyama, Testing scenarios of primordial black holes being the seeds of supermassive black holes by ultracompact minihalos and CMBµ-distortions, Phys. Rev. D90, 083514 (2014), arXiv:1405.5999 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2014

  45. [45]

    M. U. Kobayashi and K. Kohri, NANOGrav 15-year gravitational-wave signals from bi- nary supermassive black-holes seeded by primordial black holes, arXiv e-prints (2025), arXiv:2511.04210 [astro-ph.CO]

    work page arXiv 2025

  46. [46]

    Constraints on small-scale primordial power by annihilation signals from extragalactic dark matter minihalos

    T. Nakama, T. Suyama, K. Kohri, and N. Hiroshima, Constraints on small-scale primordial power by annihilation signals from extragalactic dark matter minihalos, Phys. Rev. D97, 023539 (2018), arXiv:1712.08820 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2018

  47. [47]

    Inman and K

    D. Inman and K. Kohri, Enhanced small-scale structure in the cosmic dark ages, Phys. Rev. D107, 123513 (2023), arXiv:2207.14735 [astro-ph.CO]

    work page arXiv 2023

  48. [48]

    Ito and K

    M. Ito and K. Omukai, First star formation in extremely early epochs, PASJ76, 850 (2024), arXiv:2405.10073 [astro-ph.GA]

    work page arXiv 2024

  49. [49]

    W. Qin, S. Kumar, P. Natarajan, and N. Weiner, Not-quite-primordial black holes, arXiv e-prints , arXiv:2506.13858 (2025), arXiv:2506.13858 [astro-ph.CO]

    work page arXiv 2025

  50. [50]

    Precise Measurements of Primordial Power Spectrum with 21 cm Fluctuations

    K. Kohri, Y. Oyama, T. Sekiguchi, and T. Takahashi, Precise Measurements of Primordial Power Spectrum with 21 cm Fluctuations, JCAP10, 065, arXiv:1303.1688 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv

  51. [51]

    Relaxing Constraints on Inflation Models with Curvaton

    T. Moroi, T. Takahashi, and Y. Toyoda, Relaxing constraints on inflation models with curva- ton, Phys. Rev. D72, 023502 (2005), arXiv:hep-ph/0501007

    work page internal anchor Pith review Pith/arXiv arXiv 2005

  52. [52]

    Non-Gaussianity, Spectral Index and Tensor Modes in Mixed Inflaton and Curvaton Models

    K. Ichikawa, T. Suyama, T. Takahashi, and M. Yamaguchi, Non-Gaussianity, Spectral Index and Tensor Modes in Mixed Inflaton and Curvaton Models, Phys. Rev. D78, 023513 (2008), arXiv:0802.4138 [astro-ph]

    work page internal anchor Pith review Pith/arXiv arXiv 2008

  53. [53]

    Low-scale inflation

    G. German, G. G. Ross, and S. Sarkar, Low scale inflation, Nucl. Phys. B608, 423 (2001), arXiv:hep-ph/0103243. 16

    work page internal anchor Pith review Pith/arXiv arXiv 2001