Pith Number

pith:QC7KCAVS

pith:2026:QC7KCAVSJ66DGHRVBWPD34TJUC

not attested not anchored not stored refs resolved

Peculiar-velocity distribution functions and 21-cm fluctuations

Marc Kamionkowski, Ryan Yuran Zhang

Accounting for the difference between parallel and perpendicular peculiar-velocity correlations improves 21-cm fluctuation predictions.

arxiv:2605.15287 v1 · 2026-05-14 · astro-ph.CO · hep-th

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Record completeness

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2 Internet Archive

3 Author claim open · sign in to claim

4 Citations open

5 Replications open

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The bundle contains the canonical record plus signed events. A mirror can host it anywhere and recompute the same current state with the deterministic merge algorithm.

Claims

C1strongest claim

The error that arises in predictions for 21-cm fluctuations if this subtlety is overlooked is generally less than a few percent, but it can be larger for some values of wavenumber k and redshift z if there are cancellations between different contributions to the total signal.

C2weakest assumption

The peculiar velocity field follows the two-point statistics derived from linear perturbation theory in the standard cosmological model, allowing the joint PDF of velocity squares to be computed from the parallel and perpendicular components (as described in the abstract's account of the velocity correlations and prior simplifying assumption).

C3one line summary

Derives the joint PDF for squared peculiar velocities at separated points and shows that neglecting directional anisotropy in velocity correlations causes errors of a few percent or less in 21-cm fluctuation predictions.

References

11 extracted · 11 resolved · 2 Pith anchors

[1] Givans, Jahmour J. and Kamionkowski, Marc. Hints of tensions in the cosmic microwave background temperature and polarization quadrupoles. 2023. arXiv:2311.06196 2023

[2] Robust Velocity-induced Acoustic Oscillations at Cosmic Dawn 2019 · doi:10.1103/physrevd.100.063538

[3] Standard Ruler at Cosmic Dawn 2019 · doi:10.1103/physrevlett.123.131301

[4] and Binnie, Thomas and Mu\ noz, Julian B 2021 · doi:10.1103/physrevd.104.063536

[5] Detecting patchy reionization in the CMB 2017 · doi:10.1103/physrevlett.119.021301

Formal links

2 machine-checked theorem links

Receipt and verification

First computed	2026-05-20T00:00:50.739995Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

80bea102b24fbc331e350d9e3df269a0845806f880fd05f4b0df7c50eafa08b1

Aliases

arxiv: 2605.15287 · arxiv_version: 2605.15287v1 · doi: 10.48550/arxiv.2605.15287 · pith_short_12: QC7KCAVSJ66D · pith_short_16: QC7KCAVSJ66DGHRV · pith_short_8: QC7KCAVS

Agent API

Resolver JSON Graph JSON Events JSON Schema Signing key

Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/QC7KCAVSJ66DGHRVBWPD34TJUC \
  | jq -c '.canonical_record' \
  | python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: 80bea102b24fbc331e350d9e3df269a0845806f880fd05f4b0df7c50eafa08b1

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "9e87f4a703f9b10357d1ac416654169c25f883267e1e339733259d367a5bb31a",
    "cross_cats_sorted": [
      "hep-th"
    ],
    "license": "http://creativecommons.org/licenses/by/4.0/",
    "primary_cat": "astro-ph.CO",
    "submitted_at": "2026-05-14T18:01:06Z",
    "title_canon_sha256": "e5bdbdb2cf965e5c299fb5f9e0b158083a67d2aedfc4493ae391d5fcea5055c5"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2605.15287",
    "kind": "arxiv",
    "version": 1
  }
}