A local Universe catalogue of structures and voids dynamically identified using Cosmic-Flows4++ZOA peculiar velocities
Pith reviewed 2026-06-27 05:43 UTC · model grok-4.3
The pith
Peculiar velocity data yields catalogues of 37 voids and 42 knots in the local Universe.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We present a comprehensive catalogue of the main local Universe cosmic web voids and knots, using the updated CosmicFlows-4++ Zone of Avoidance (CF4++ZOA) catalogue out to redshift z=0.1. To do this we use the V-web algorithm which provides a dynamically motivated map of the local cosmic web, tracing the major expanding and converging regions of the local Universe. The robustness of the catalogue is assessed using the ensemble of Hamiltonian Monte Carlo realizations of the CF4++ZOA reconstruction. We additionally remove any structure that exceeds the survey boundaries and present catalogues of 37 voids and 42 knot regions within the reconstructed survey volume. The identified emptying region
What carries the argument
The V-web algorithm, which classifies regions of the reconstructed velocity field into expanding voids and converging knots.
If this is right
- 37 voids are identified with effective radii ranging from 13 to 38 h^{-1}Mpc.
- 42 knot regions are identified with volumes ranging from 10^4 to 3.3x10^5 h^{-3} Mpc^3.
- Structures that exceed the survey boundaries are excluded from the final catalogues.
- The identification remains consistent across the ensemble of Hamiltonian Monte Carlo realizations of the reconstruction.
Where Pith is reading between the lines
- The velocity-based catalogue can be cross-checked against galaxy density maps in the same volume to test consistency of web classification methods.
- These regions supply a local benchmark for comparing observed structure growth against N-body simulations.
- The method could be applied to future deeper peculiar velocity surveys to extend the catalogue beyond z=0.1.
Load-bearing premise
The V-web algorithm applied to the CF4++ZOA velocity reconstruction accurately separates dynamically expanding voids from converging knots without significant contamination from survey boundaries or reconstruction noise.
What would settle it
An independent reconstruction of the local velocity field that produces a substantially different number, size distribution, or spatial arrangement of voids and knots would falsify the catalogue.
Figures
read the original abstract
Cosmic voids and superclusters are among the largest structures in the Universe and provide complementary probes of the growth of large-scale structure and the underlying gravitational field. We present a comprehensive catalogue of the main local Universe cosmic web voids and knots, using the updated CosmicFlows-4++ Zone of Avoidance (CF4++ZOA) catalogue out to redshift z=0.1. To do this we use the V-web algorithm which provides a dynamically motivated map of the the local cosmic web, tracing the major expanding and converging regions of the local Universe. The robustness of the catalogue is assessed using the ensemble of Hamiltonian Monte Carlo realizations of the CF4++ZOA reconstruction. We additionally remove any structure that exceeds the survey boundaries and present catalogues of 37 voids and 42 knot regions within the reconstructed survey volume. The identified emptying regions (voids) have effective radii ranging from 13 to 38 h-1Mpc. The high density converging regions (knots) have volumes ranging from 10^4 to 3.3x10^5 h-3 Mpc^3.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript presents catalogues of 37 voids and 42 knot regions in the local Universe (z < 0.1) identified via the V-web algorithm applied to the CF4++ZOA peculiar velocity reconstruction. Voids are reported with effective radii 13–38 h^{-1} Mpc; knots have volumes 10^4–3.3 imes10^5 h^{-3} Mpc^3. Robustness is assessed via the HMC ensemble of reconstructions, with structures exceeding survey boundaries removed.
Significance. If the identifications hold, the catalogue supplies a dynamically motivated reference for the local cosmic web that can be used to study environmental effects on galaxies, compare with simulations, and complement other tracers such as galaxy surveys or weak lensing. The work applies an established algorithm to an updated velocity field, extending prior catalogues in a direct and useful manner.
minor comments (2)
- [Abstract] Abstract: typographical error in 'map of the the local cosmic web' (duplicate 'the').
- [Abstract] Abstract (robustness paragraph): the statement that robustness was assessed via the HMC ensemble would benefit from a brief quantitative summary (e.g., fraction of structures stable across realizations or typical boundary-exclusion rate) for clarity, even though the central catalogue counts are presented as the main result.
Simulated Author's Rebuttal
We thank the referee for their positive summary, assessment of significance, and recommendation of minor revision. No major comments were provided in the report.
Circularity Check
Direct application of existing V-web algorithm to external catalogue; no circular derivation
full rationale
The paper applies the pre-existing V-web algorithm to the independent CF4++ZOA velocity reconstruction to identify voids and knots, then reports counts (37 voids, 42 knots), size ranges, and boundary/ensemble robustness checks. No equations, self-definitions, fitted parameters renamed as predictions, or load-bearing self-citations appear in the derivation chain. The central output is a catalogue from direct algorithmic processing of external data, making the result self-contained against external benchmarks with no reduction to inputs by construction.
Axiom & Free-Parameter Ledger
Reference graph
Works this paper leans on
-
[1]
Qin, F. and Blake, C. and Howlett, C. and Turner, R. J. and Lodha, K. and Bautista, J. and Lai, Y. and Amsellem, A. J. and Aguilar, J. and Ahlen, S. and Bianchi, D. and Brooks, D. and BenZvi, S. and Carr, A. and Chaussidon, E. and Claybaugh, T. and Cuceu, A. and Macorra, A. de la and Douglass, K. and Doel, P. and Ferraro, S. and Font-Ribera, A. and Forero...
-
[2]
Lai, Y. and Howlett, C. and Aguilar, J. and Ahlen, S. and Amsellem, A. J. and Bautista, J. and BenZvi, S. and Bianchi, D. and Blake, C. and Brooks, D. and Carr, A. and Claybaugh, T. and Davis, T. M. and Macorra, A. de la and Doel, P. and Douglass, K. and Ferraro, S. and Font-Ribera, A. and Forero-Romero, J. E. and Gaztañaga, E. and Gutierrez, G. and Guy, ...
work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2512.03229
-
[3]
Turner, Ryan J. , month = nov, year =. Cosmology with. doi:10.48550/arXiv.2411.19484 , journal =
-
[4]
The clustering of galaxies in the completed. , author =. 2017 , note =. doi:10.1093/mnras/stw2495 , number =
-
[5]
Galaxy Superclusters and Their Complexes in the Cosmic Web. Universe , keywords =. doi:10.3390/universe11060167 , archivePrefix =. 2505.22082 , primaryClass =
-
[6]
, author =. 2020 , note =. doi:10.1093/mnras/stz3157 , number =
-
[7]
Sinha, Manodeep and Garrison, Lehman H. , month = jan, year =. Corrfunc:. doi:10.1007/978-981-13-7729-7_1 , booktitle =
-
[8]
H., Fagrelius, P., Fanning, K., et al
The. , author =. 2023 , note =. doi:10.3847/1538-3881/ac9ab1 , number =
-
[9]
Survey. , author =. 2023 , note =. doi:10.3847/1538-3881/ad0832 , number =
-
[10]
Target selection for the. , author =. 2023 , note =. doi:10.1093/mnras/stad2200 , number =
-
[11]
DESI peculiar velocity survey – Fundamental Plane , volume=
, author =. 2025 , note =. doi:10.1093/mnras/staf700 , number =
-
[12]
The. , author =. 2025 , note =. doi:10.3847/1538-4357/ad9391 , number =
-
[13]
Overview of the. , author =. 2024 , keywords =. doi:10.3847/1538-3881/ad76a4 , number =
-
[14]
N., Doel, P., Gutierrez, G., et al
The. , author =. 2024 , note =. doi:10.3847/1538-3881/ad45fe , number =
-
[15]
Constraining modified gravity scenarios with the. , author =. 2024 , note =. doi:10.1093/mnras/stae1718 , number =
-
[16]
Lensing is low: cosmology, galaxy formation or new physics? , volume =. , author =. 2017 , note =. doi:10.1093/mnras/stx258 , number =
-
[17]
Using peculiar velocity surveys to constrain the growth rate of structure with the wide-angle effect , volume =. , author =. 2023 , note =. doi:10.1093/mnras/stac3252 , number =
-
[18]
, volume = 474, number = 4, pages =
, author =. 2018 , note =. doi:10.1093/mnras/stx2820 , number =
-
[19]
Computing in Science and Engineering , keywords =
Matplotlib:. Computing in Science and Engineering , author =. 2007 , keywords =. doi:10.1109/MCSE.2007.55 , number =
-
[20]
Why your model parameter confidences might be too optimistic. , author =. 2007 , note =. doi:10.1051/0004-6361:20066170 , number =
-
[21]
Array programming with. , author =. 2020 , note =. doi:10.1038/s41586-020-2649-2 , number =
-
[22]
The. , author =. 2023 , note =. doi:10.3847/1538-3881/accff8 , number =
-
[23]
The. , author =. 2023 , note =. doi:10.3847/1538-3881/acb212 , number =
-
[24]
Statistical Science , year = 1992, month = jan, volume =
Gelman, Andrew and Rubin, Donald B. , month = jan, year =. Inference from. doi:10.1214/ss/1177011136 , journal =
-
[25]
J.\ Open Source Software , year = 2016, month = jun, volume =
Foreman-Mackey, Daniel , month = jun, year =. corner.py:. doi:10.21105/joss.00024 , journal =
-
[26]
and Lang, Dustin and Goodman, Jonathan , year=
emcee:. , author =. 2013 , note =. doi:10.1086/670067 , number =
-
[27]
doi:10.1016/C2017-0-01943-2 , author =
Modern. doi:10.1016/C2017-0-01943-2 , author =
-
[28]
Douglass, K. and BenZvi, S. and Uberoi, N. and Howlett, C. and Saulder, C. and Said, K. and Demina, R. and Aguilar, J. and Ahlen, S. and Aldering, G. and Bianchi, D. and Brooks, D. and Claybaugh, T. and Cuceu, A. and Davis, T. M. and Dawson, K. S. and de la Macorra, A. and Font-Ribera, A. and Forero-Romero, J. E. and Gaztanaga, E. and Gontcho, S. Gontcho ...
-
[29]
Overview of the. , author =. 2019 , note =. doi:10.3847/1538-3881/ab089d , number =
-
[30]
Data Release 1 of the Dark Energy Spectroscopic Instrument
Data. 2025 , note =. doi:10.48550/arXiv.2503.14745 , journal =
work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2503.14745 2025
-
[31]
The. , author =. 2024 , note =. doi:10.3847/1538-3881/ad3217 , number =
-
[32]
Validation of the. , author =. 2024 , note =. doi:10.3847/1538-3881/ad0b08 , number =
-
[33]
Overview of the. , author =. 2022 , note =. doi:10.3847/1538-3881/ac882b , number =
-
[34]
The. , author =. 2024 , note =. doi:10.3847/2041-8213/ad6f9f , number =
-
[35]
Davis, M. and Peebles, P. J. E. , month = apr, year =. A survey of galaxy redshifts. doi:10.1086/160884 , journal =
-
[36]
On the correlations of galaxy peculiar velocities and their covariance , volume =. , author =. 2024 , note =. doi:10.1093/mnras/stad3217 , number =
-
[37]
The. , author =. 2018 , note =. doi:10.3847/1538-3881/aabc4f , number =
-
[38]
Astropy:. 2013 , note =. doi:10.1051/0004-6361/201322068 , journal =
-
[39]
, author =. 2025 , note =. doi:10.1103/tr6y-kpc6 , number =
-
[40]
Turner, R. J. and Blake, C. and Qin, F. and Aguilar, J. and Ahlen, S. and Amsellem, A. J. and Bautista, J. and BenZvi, S. and Bianchi, D. and Brooks, D. and Carr, A. and Chaussidon, E. and Claybaugh, T. and Cuceu, A. and de la Macorra, A. and Doel, P. and Douglass, K. and Ferraro, S. and Font-Ribera, A. and Forero-Romero, J. E. and Gaztañaga, E. and Gontc...
-
[41]
The clustering of galaxies in the completed. MNRAS , author =. 2017 , note =. doi:10.1093/mnras/stx721 , number =
-
[42]
Alcock, C. and Paczynski, B. , month = oct, year =. An evolution free test for non-zero cosmological constant , volume =. doi:10.1038/281358a0 , journal =
-
[43]
The Astrophysical Journal , author =. 2015 , pages =. doi:10.1088/0004-637X/802/1/63 , abstract =
-
[44]
and Bauer, Franz Erik and Bean, Rachel and Beckett, George and Biswas, Rahul and Bogart, Joanne R
DESC), The LSST Dark Energy Science Collaboration (LSST and Abolfathi, Bela and Alonso, David and Armstrong, Robert and Aubourg, Éric and Awan, Humna and Babuji, Yadu N. and Bauer, Franz Erik and Bean, Rachel and Beckett, George and Biswas, Rahul and Bogart, Joanne R. and Boutigny, Dominique and Chard, Kyle and Chiang, James and Claver, Chuck F. and Cohen...
-
[45]
Constraining the. , author =. 2025 , note =. doi:10.1093/mnras/stae2575 , number =
-
[46]
The. , author =. 2024 , note =. doi:10.1093/mnras/stae359 , number =
-
[47]
The. 2005 , note =. doi:10.48550/arXiv.astro-ph/0510346 , journal =
work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.astro-ph/0510346 2005
-
[48]
Full-sky. , author =. 2017 , note =. doi:10.3847/1538-4357/aa943d , number =
-
[49]
Fast and accurate Gaia-unWISE quasar mock catalogs from LPT and Eulerian bias
Sinigaglia, Francesco and Kitaura, Francisco-Shu and Shiferaw, Mahlet and Favole, Ginevra and Storey-Fisher, Kate and Arsenov, Nestor , month = sep, year =. Fast and accurate. doi:10.48550/arXiv.2509.15890 , journal =
work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2509.15890
-
[50]
The. , author =. 2024 , note =. doi:10.3847/2041-8213/ad66bf , number =
-
[51]
Mapping the. , author =. 2022 , note =. doi:10.3847/1538-4357/ac5112 , number =
-
[52]
The emperor's new arc: gigaparsec patterns abound in a \ ensuremathŁambdaCDM universe , volume =. , author =. 2025 , note =. doi:10.1093/mnrasl/slaf021 , number =
-
[53]
Cosmic voids and void lensing in the. , author =. 2017 , note =. doi:10.1093/mnras/stw2745 , number =
-
[54]
Quaia, the. , author =. 2024 , note =. doi:10.3847/1538-4357/ad1328 , number =
-
[55]
Sinigaglia, F. and Kitaura, F.-S. and Nagamine, K. and Oku, Y. and Balaguera-Antolínez, A. , month = feb, year =. Field-level. doi:10.1051/0004-6361/202346931 , journal =
-
[56]
The. , author =. 2023 , note =. doi:10.1093/mnras/stad2419 , number =
-
[57]
Sartori, S. and Vielzeuf, P. and Escoffier, S. and Cousinou, M. C. and Kovács, A. and DeRose, J. and Ahlen, S. and Bianchi, D. and Brooks, D. and Burtin, E. and Claybaugh, T. and de la Macorra, A. and Forero-Romero, J. E. and Garcia-Bellido, J. and Gontcho A Gontcho, S. and Gutierrez, G. and Honscheid, K. and Kehoe, R. and Kirkby, D. and Kisner, T. and La...
-
[58]
, author =. 2025 , note =. doi:10.3847/1538-4357/adb559 , number =
-
[59]
The. , author =. 2020 , note =. doi:10.3847/1538-4357/ab6f05 , number =
-
[60]
Complementary cosmological simulations , volume =
Rácz, Gábor and Kiessling, Alina and Csabai, István and Szapudi, István , month = apr, year =. Complementary cosmological simulations , volume =. doi:10.1051/0004-6361/202245211 , journal =
-
[61]
, author =. 2008 , note =. doi:10.1111/j.1365-2966.2008.13180.x , number =
-
[62]
Beyond. , author =. 2019 , note =. doi:10.1103/PhysRevD.100.023504 , number =
-
[63]
Testing cosmology with a catalogue of voids in the. , author =. 2016 , note =. doi:10.1093/mnras/stw1340 , number =
-
[64]
2020, title Planck 2018 results
Planck 2018 results. 2020 , note =. doi:10.1051/0004-6361/201833910 , journal =
-
[65]
Journal of Korean Astronomical Society , author =
Large. Journal of Korean Astronomical Society , author =. 2015 , note =. doi:10.5303/JKAS.2015.48.1.75 , number =
-
[66]
Beyond two-point statistics: using the minimum spanning tree as a tool for cosmology , volume =. , author =. 2020 , note =. doi:10.1093/mnras/stz3075 , number =
-
[67]
Can a supervoid explain the cold spot? , volume =. , author =. 2014 , note =. doi:10.1103/PhysRevD.90.103510 , number =
-
[68]
LSST Science Book, Version 2.0
2009 , note =. doi:10.48550/arXiv.0912.0201 , journal =
work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.0912.0201 2009
-
[69]
A. , author =. 2022 , note =. doi:10.1093/mnras/stac2204 , number =
-
[70]
A. , author =. 2016 , note =. doi:10.3847/2041-8205/830/1/L19 , number =
-
[71]
Seeing patterns in noise: gigaparsec-scale `structures' that do not violate homogeneity , volume =. , author =. 2013 , note =. doi:10.1093/mnras/stt1028 , number =
-
[72]
A. , author =. 2017 , note =. doi:10.3847/1538-4357/835/2/161 , number =
-
[73]
Liu, A. and Bulbul, E. and Kluge, M. and Ghirardini, V. and Zhang, X. and Sanders, J. S. and Artis, E. and Bahar, Y. E. and Balzer, F. and Brüggen, M. and Clerc, N. and Comparat, J. and Garrel, C. and Gatuzz, E. and Grandis, S. and Lamer, G. and Merloni, A. and Migkas, K. and Nandra, K. and Predehl, P. and Ramos-Ceja, M. E. and Reiprich, T. H. and Seppi, ...
-
[74]
Tracing the cosmic web , volume =. , author =. 2018 , note =. doi:10.1093/mnras/stx1976 , number =
-
[75]
Cross-correlation of cosmic voids with thermal. , author =. 2024 , note =. doi:10.1093/mnras/stad3396 , number =
-
[76]
Levi, Michael and Bebek, Chris and Beers, Timothy and Blum, Robert and Cahn, Robert and Eisenstein, Daniel and Flaugher, Brenna and Honscheid, Klaus and Kron, Richard and Lahav, Ofer and McDonald, Patrick and Roe, Natalie and Schlegel, David and. The. 2013 , note =. doi:10.48550/arXiv.1308.0847 , journal =
work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.1308.0847 2013
-
[77]
The. , author =. 2013 , note =. doi:10.1088/2041-8205/762/2/L20 , number =
-
[78]
Evidence for a high-z. , author =. 2022 , note =. doi:10.1093/mnras/stac903 , number =
-
[79]
The. , author =. 2022 , note =. doi:10.1093/mnras/stab3309 , number =
-
[80]
, author =. 2014 , note =. doi:10.1088/0004-6256/147/5/108 , number =
discussion (0)
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