In-situ globular clusters in alternative dark matter Milky Way galaxies: a first approach to fuzzy and core-like dark matter theories
Pith reviewed 2026-05-18 10:34 UTC · model grok-4.3
The pith
In fuzzy dark matter, Milky Way globular cluster systems grow more massive and extended than in cold dark matter once the particle mass exceeds a threshold value.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
For m22 below 7 the inner potential remains steep and centrally concentrated because baryons dominate, confining globular cluster orbits and yielding less massive, more compact systems than in cold dark matter. At m22 approximately 7 the properties match those found in cold dark matter. For m22 above 7 the dark matter itself becomes compact and globally dominant, producing a deeper and more extended gravitational potential that supports a wider range of stable orbits and therefore more massive and spatially extended globular cluster systems.
What carries the argument
Orbital integrations performed on globular clusters that begin with identical normalized E-Lz distributions inside matched cold dark matter and fuzzy dark matter halos drawn from TNG50 cosmological assembly histories.
Load-bearing premise
Globular cluster populations are initialized with the same normalized energy and angular momentum distributions in both fuzzy and cold dark matter halos, which assumes dark matter type does not alter cluster formation or initial placement.
What would settle it
A measurement of Milky Way in-situ globular cluster masses and spatial extents that shows no increase in size or mass for high m22 values compared with cold dark matter expectations would falsify the predicted regime transition.
Figures
read the original abstract
We present a first analysis of the dynamics of in-situ globular clusters (GCs) in Milky Way (MW)-like galaxies embedded in fuzzy dark matter (FDM) halos, combining cosmological assembly histories from the TNG50 simulation with dedicated orbital integrations and analytical models. GC populations are initialized with identical distributions in normalized $E$-$L_{z}$ in matched CDM and FDM halos. In a universe dominated by FDM, we identify three distinct regimes for the in-situ GC population depending on the particle mass $m_{22} \equiv m_{\chi}/ 10^{-22}~\mathrm{eV}$. For $m_{22} < 7$, baryons dominate the inner potential, which remains steep and centrally concentrated, confining GC orbits to a narrow region and producing less massive, more compact systems than in CDM. For $m_{22} \sim 7$, GC properties resemble those in CDM, with similar mass and spatial distributions. For $m_{22} > 7$, the dark matter becomes both compact and globally dominant, generating a deeper and more extended gravitational potential that supports a wider range of stable GC orbits, resulting in more massive and spatially extended GC systems. Finally, we extend our framework to make predictions for GC populations in alternative DM models, including warm dark matter and self-interacting dark matter, in both MW-like and dwarf galaxies. Our findings demonstrate that in-situ GC systems offer a sensitive and independent probe of the underlying DM physics, opening new avenues for observational constraints with upcoming Euclid.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper presents a first analysis of in-situ globular cluster dynamics in Milky Way-like galaxies embedded in fuzzy dark matter halos. It combines cosmological assembly histories from the TNG50 simulation with dedicated orbital integrations and analytical models. GC populations are initialized with identical distributions in normalized E-Lz in matched CDM and FDM halos. Three regimes are identified depending on the FDM particle mass m22: for m22<7 baryons dominate the inner potential producing less massive compact GC systems; at m22~7 properties resemble CDM; for m22>7 DM is compact and dominant yielding a deeper extended potential that supports more massive and spatially extended GC systems. The framework is extended to predictions for WDM, SIDM and other galaxies.
Significance. If the results hold, the work offers a new independent probe of alternative dark matter physics through in-situ GC populations, with potential observational constraints from Euclid. Strengths include the use of external TNG50 assembly histories combined with dedicated integrations and the extension to multiple DM models in both MW-like and dwarf galaxies; this provides falsifiable predictions grounded in orbital stability rather than ad-hoc fitting.
major comments (2)
- [Abstract and methods description] The identification of the m22=7 transition and the three regimes lacks quantitative details on how the boundaries were determined from the orbital integrations, including the specific integration methods, error analysis, and sensitivity to modeling choices such as potential matching between CDM and FDM halos.
- [Abstract] The central claim for m22>7 (deeper extended potential supporting wider stable orbits and thus more massive/extended GC systems) rests on initializing GC populations with identical normalized E-Lz distributions in matched CDM/FDM halos; this assumes DM type does not alter formation or initial placement, which is load-bearing and requires explicit justification or tests against DM-dependent formation effects.
minor comments (1)
- [Abstract] The abstract states that the framework is extended to WDM and SIDM but provides no specifics on the implementation or resulting predictions.
Simulated Author's Rebuttal
We thank the referee for their constructive and positive assessment of our work. We address each major comment below and have revised the manuscript accordingly to improve clarity and robustness.
read point-by-point responses
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Referee: [Abstract and methods description] The identification of the m22=7 transition and the three regimes lacks quantitative details on how the boundaries were determined from the orbital integrations, including the specific integration methods, error analysis, and sensitivity to modeling choices such as potential matching between CDM and FDM halos.
Authors: We agree that additional quantitative details would strengthen the presentation. In the revised manuscript we have expanded the Methods section with a new subsection that specifies the orbital integration scheme, reports energy conservation errors at the level of 10^{-6} over 10 Gyr, and describes how the m22=7 boundary was identified as the point at which the FDM core radius becomes comparable to the baryonic scale length (thereby shifting inner-potential dominance). We also include a sensitivity test demonstrating that the three-regime classification remains unchanged for potential-matching tolerances between 3% and 10% in the inner 5 kpc. revision: yes
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Referee: [Abstract] The central claim for m22>7 (deeper extended potential supporting wider stable orbits and thus more massive/extended GC systems) rests on initializing GC populations with identical normalized E-Lz distributions in matched CDM/FDM halos; this assumes DM type does not alter formation or initial placement, which is load-bearing and requires explicit justification or tests against DM-dependent formation effects.
Authors: This is a fair observation. Our controlled comparison deliberately adopts identical normalized E-Lz distributions drawn from the TNG50 assembly histories in order to isolate the purely dynamical effect of the altered gravitational potential. We have added an explicit justification paragraph in the revised Methods and a dedicated limitations subsection in the Discussion: because in-situ GC formation is driven primarily by baryonic processes, matching the initial orbital distribution across DM models is a reasonable first-approach approximation. We acknowledge that DM-dependent formation physics could modify the initial conditions and have therefore performed a robustness test in which the width of the initial E-Lz distribution is varied by ±20%; the qualitative trends for m22>7 persist. Full hydrodynamical FDM simulations will be needed to relax this assumption in future work. revision: partial
Circularity Check
No significant circularity: results derive from orbital integrations on TNG50-matched halos with explicit shared initial conditions
full rationale
The paper combines external cosmological assembly histories from the TNG50 simulation with dedicated orbital integrations and analytical models. GC populations are initialized with identical distributions in normalized E-Lz across matched CDM and FDM halos as an explicit methodological assumption, after which the outcomes (mass and spatial distributions) are computed from the differing gravitational potentials. The three regimes for m22 are identified by direct comparison of these computed results rather than by any self-referential definition, fitted parameter renamed as prediction, or load-bearing self-citation. No equation or step reduces the reported GC properties to the inputs by construction; the derivation remains independent of the target claims and is grounded in external simulation data plus new integrations.
Axiom & Free-Parameter Ledger
free parameters (1)
- m22 transition value =
7
axioms (1)
- domain assumption Identical initial distributions in normalized E-Lz for GCs in CDM and FDM halos
Lean theorems connected to this paper
-
IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
GC populations are initialized with identical distributions in normalized E-Lz in matched CDM and FDM halos... For m22 >7, the dark matter becomes both compact and globally dominant, generating a deeper and more extended gravitational potential
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IndisputableMonolith/Foundation/AlexanderDuality.leanalexander_duality_circle_linking unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
We identify three distinct regimes for the in-situ GC population depending on the particle mass m22
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
- [1]
-
[3]
Amorisco, N. C. & Loeb, A. 2018b, arXiv e-prints, arXiv:1808.00464
work page internal anchor Pith review Pith/arXiv arXiv
-
[4]
Armengaud, E., Palanque-Delabrouille, N., Yèche, C., Marsh, D. J. E., & Baur, J. 2017, MNRAS, 471, 4606
work page 2017
- [5]
-
[6]
Bode, P., Ostriker, J. P., & Turok, N. 2001, ApJ, 556, 93 Böhmer, C. G. & Harko, T. 2007, J. Cosmology Astropart. Phys., 2007, 025
work page 2001
- [7]
-
[8]
2025, arXiv e-prints, arXiv:2506.13254
Boldrini, P., Di Matteo, P., Laporte, C., et al. 2025, arXiv e-prints, arXiv:2506.13254
-
[9]
Bond, J. R., Efstathiou, G., & Silk, J. 1980, Phys. Rev. Lett., 45, 1980
work page 1980
-
[10]
Bullock, J. S. & Boylan-Kolchin, M. 2017, ARA&A, 55, 343
work page 2017
- [11]
- [12]
- [13]
-
[14]
Chan, H. Y . J., Ferreira, E. G. M., May, S., Hayashi, K., & Chiba, M. 2022, MNRAS, 511, 943
work page 2022
- [15]
-
[16]
T., Schive, H.-Y ., & Chiueh, T
Chiang, B. T., Schive, H.-Y ., & Chiueh, T. 2021, Phys. Rev. D, 103, 103019
work page 2021
-
[17]
2025, MNRAS, 537, 2535 Colín, P., Avila-Reese, V ., & Valenzuela, O
Claeyssens, A., Adamo, A., Messa, M., et al. 2025, MNRAS, 537, 2535 Colín, P., Avila-Reese, V ., & Valenzuela, O. 2000, ApJ, 542, 622
work page 2025
-
[18]
Correa, C. A. 2021, MNRAS, 503, 920
work page 2021
-
[19]
A., Schaller, M., Schaye, J., et al
Correa, C. A., Schaller, M., Schaye, J., et al. 2025, MNRAS, 536, 3338 de Laix, A. A., Scherrer, R. J., & Schaefer, R. K. 1995, ApJ, 452, 495 de Souza, R. S., Mesinger, A., Ferrara, A., et al. 2013, MNRAS, 432, 3218
work page 2025
-
[20]
Dodelson, S. & Widrow, L. M. 1994, Phys. Rev. Lett., 72, 17 Dutta Chowdhury, D., van den Bosch, F. C., Robles, V . H., et al. 2021, ApJ, 916, 27
work page 1994
-
[21]
Eberhardt, A. & Ferreira, E. G. M. 2025, arXiv e-prints, arXiv:2507.00705
-
[22]
A., Freundlich, J., Combes, F., & Halle, A
El-Zant, A. A., Freundlich, J., Combes, F., & Halle, A. 2020, MNRAS, 492, 877
work page 2020
-
[23]
2021, MNRAS, 507, 4211 Euclid Collaboration, Mellier, Y ., Abdurro’uf, et al
Engler, C., Pillepich, A., Pasquali, A., et al. 2021, MNRAS, 507, 4211 Euclid Collaboration, Mellier, Y ., Abdurro’uf, et al. 2025, A&A, 697, A1
work page 2021
-
[24]
Fischer, M. S. & Sagunski, L. 2024, A&A, 690, A299 Gaia Collaboration, Brown, A. G. A., Vallenari, A., et al. 2021, A&A, 649, A1
work page 2024
-
[25]
Garzilli, A., Magalich, A., Theuns, T., et al. 2019, MNRAS, 489, 3456
work page 2019
- [26]
- [27]
-
[28]
Hogan, C. J. & Dalcanton, J. J. 2000, Phys. Rev. D, 62, 063511
work page 2000
- [29]
-
[30]
Hui, L., Ostriker, J. P., Tremaine, S., & Witten, E. 2017, Phys. Rev. D, 95, 043541 Iršiˇc, V ., Viel, M., Haehnelt, M. G., Bolton, J. S., & Becker, G. D. 2017, Phys. Rev. Lett., 119, 031302
work page 2017
- [31]
-
[32]
Kaplinghat, M., Tulin, S., & Yu, H.-B. 2016, Phys. Rev. Lett., 116, 041302
work page 2016
-
[33]
Kluge, M., Hatch, N. A., Montes, M., et al. 2025, A&A, 697, A13
work page 2025
-
[34]
Kobayashi, T., Murgia, R., De Simone, A., Irši ˇc, V ., & Viel, M. 2017, Phys. Rev. D, 96, 123514
work page 2017
- [35]
-
[36]
Kruijssen, J. M. D., Pelupessy, F. I., Lamers, H. J. G. L. M., Portegies Zwart, S. F., & Icke, V . 2011, MNRAS, 414, 1339
work page 2011
-
[37]
Lancaster, L., Giovanetti, C., Mocz, P., et al. 2020, J. Cosmology Astropart. Phys., 2020, 001 Lançon, A., Larsen, S., V oggel, K., et al. 2021, in SF2A-2021: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics, ed. A. Siebert, K. Baillié, E. Lagadec, N. Lagarde, J. Malzac, J. B. Marquette, M. N’Diaye, J. Richard, & O. Ve...
work page 2020
-
[38]
Lovell, M. R., Frenk, C. S., Eke, V . R., et al. 2014, MNRAS, 439, 300 Macciò, A. V ., Paduroiu, S., Anderhalden, D., Schneider, A., & Moore, B. 2012, MNRAS, 424, 1105 Markoviˇc, K. & Viel, M. 2014, PASA, 31, e006
work page 2014
-
[39]
Marsh, D. J. E. & Niemeyer, J. C. 2019, Phys. Rev. Lett., 123, 051103
work page 2019
-
[40]
Marsh, D. J. E. & Silk, J. 2014, MNRAS, 437, 2652
work page 2014
-
[41]
Massari, D., Dalessandro, E., Erkal, D., et al. 2025, A&A, 697, A8
work page 2025
- [42]
- [43]
-
[44]
Mina, M., Mota, D. F., & Winther, H. A. 2020, arXiv e-prints, arXiv:2007.04119
-
[45]
Mocz, P., Fialkov, A., V ogelsberger, M., et al. 2020, MNRAS, 494, 2027
work page 2020
- [46]
- [47]
-
[48]
Nori, M., Murgia, R., Iršiˇc, V ., Baldi, M., & Viel, M. 2019, MNRAS, 482, 3227
work page 2019
- [49]
-
[50]
Pillepich, A., Nelson, D., Springel, V ., et al. 2019, MNRAS, 490, 3196
work page 2019
-
[51]
Pillepich, A., Sotillo-Ramos, D., Ramesh, R., et al. 2024, MNRAS, 535, 1721
work page 2024
-
[52]
Pozo, A., Broadhurst, T., de Martino, I., et al. 2024, Phys. Rev. D, 110, 043534
work page 2024
-
[53]
I., Iorio, G., Agertz, O., & Fraternali, F
Read, J. I., Iorio, G., Agertz, O., & Fraternali, F. 2017, MNRAS, 467, 2019
work page 2017
- [54]
-
[55]
Rogers, K. K. & Peiris, H. V . 2021, Phys. Rev. Lett., 126, 071302
work page 2021
- [56]
-
[57]
2025a, arXiv e-prints, arXiv:2503.16367
Saifollahi, T., Lançon, A., Cantiello, M., et al. 2025a, arXiv e-prints, arXiv:2503.16367
- [58]
-
[59]
Schive, H.-Y ., Chiueh, T., & Broadhurst, T. 2014, Nature Physics, 10, 496
work page 2014
-
[60]
Schive, H.-Y ., Chiueh, T., Broadhurst, T., & Huang, K.-W. 2016, ApJ, 818, 89
work page 2016
-
[61]
Schneider, A., Smith, R. E., Macciò, A. V ., & Moore, B. 2012, MNRAS, 424, 684
work page 2012
- [62]
-
[63]
Shao, S., Gao, L., Theuns, T., & Frenk, C. S. 2013, MNRAS, 430, 2346
work page 2013
-
[64]
Spergel, D. N. & Steinhardt, P. J. 2000, Phys. Rev. Lett., 84, 3760
work page 2000
-
[65]
Urbano, M., Duc, P. A., Saifollahi, T., et al. 2024, arXiv e-prints, arXiv:2412.17672
- [66]
- [67]
-
[68]
Veltmaat, J., Schwabe, B., & Niemeyer, J. C. 2020, Phys. Rev. D, 101, 083518
work page 2020
-
[69]
G., Matarrese, S., & Riotto, A
Viel, M., Lesgourgues, J., Haehnelt, M. G., Matarrese, S., & Riotto, A. 2005, Phys. Rev. D, 71, 063534 V oggel, K., Lançon, A., Saifollahi, T., et al. 2025, A&A, 693, A251
work page 2005
-
[70]
Woo, T.-P. & Chiueh, T. 2009, ApJ, 697, 850 Article number, page 13 of 14 A&A proofs:manuscript no. main 100 101 102 Radius r [kpc] 102 103 104 105 106 107 108 109 1010 Disruption time Tdis/frelax [Gyr] MW GCs Fig. A.1.Disruption time due to FDM fluctuation-induced heating as a function of orbital distance for the 171 GCs in the MW, as provided by Gaia (V...
work page 2009
discussion (0)
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