Pith. sign in

REVIEW 2 major objections 5 minor 71 references

SKA-Low will detect at least ~2500 radio halos up to z~0.6, including over a thousand ultra-steep-spectrum systems, and will reach clusters down to ~10^14 solar masses and out to z~1.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

SKA-Low is forecast to detect ≳2500 radio halos (including ≳1000 ultra-steep-spectrum) up to z≈0.6, reaching clusters of ~10^14 M⊙ and z≈1.

T0 review reviewed 2026-07-14 challenge →

load-bearing objection Solid SKA-Low forecast paper: recalibrated Monte Carlo gives useful discovery-space numbers, but the "at least ~2500" floor is thermal-noise optimistic and should be read as an upper envelope. the 2 major comments →

arxiv 2607.10304 v1 pith:NWGALP75 submitted 2026-07-11 astro-ph.CO

Radio Halos in Galaxy Clusters as unveiled by the SKA telescope

R. Cassano , G. Di Gennaro , V. Cuciti , A. Datta , M. Balboni , G. Bernardi , A. Bonafede , A. Botteon
show 19 more authors
M. Br\"uggen G. Brunetti S. Chatterjee K. Dolag S. Ettori F. Gastaldello S. Giacintucci C. Giocoli M. Gitti R. Kale M. Pandey-Pommier G. W. Pratt M. Rahaman M. Rossetti H. J. A. R\"ottgering R. Santra K. S. L. Srikanth R. J. van Weeren T. Venturi
This is my paper
classification astro-ph.CO
keywords radio halosgalaxy clustersturbulent re-accelerationSKA-Lowultra-steep-spectrum sourcesintracluster mediumLoTSSMonte Carlo merger trees
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

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

The reading

Giant radio halos are Mpc-scale synchrotron glow that traces relativistic electrons and magnetic fields inside galaxy clusters. They appear mainly in merging systems, which fits models in which merger-driven turbulence re-accelerates electrons already present in the gas. Low-frequency surveys are essential because less energetic mergers produce halos whose spectra are so steep they are invisible at GHz frequencies. The authors take Monte Carlo merger trees calibrated on LOFAR LoTSS-DR2 statistics and forecast what SKA-Low in its AA4 configuration will see. They conclude that SKA will open a far larger region of mass and redshift space than current instruments, detecting thousands of new systems—including the long-predicted ultra-steep population—and thereby testing the turbulent re-acceleration picture across cosmic time.

Core claim

Monte Carlo simulations of cluster mergers, tuned to LoTSS-DR2 radio-halo occurrence and the observed P_150–M_500 relation, predict that SKA-Low AA4 will detect at least ~2500 radio halos out to z≈0.6 (of which ≳1000 have ultra-steep spectra) and will reveal halos in clusters as light as ~10^14 M_⊙ and as distant as z≈1, thereby supplying the statistics needed to test turbulent re-acceleration models.

What carries the argument

Homogeneous turbulent re-acceleration Monte Carlo: merger trees generate turbulent energy (a fraction η_t of the PdV work), set the spectral steepening frequency ν_s, and combine with the observed radio-power–mass relation to produce luminosity functions and number counts at 150 MHz.

Load-bearing premise

The same simple parameters for magnetic field strength, turbulent energy fraction and halo size that fit nearby LOFAR data remain valid all the way to lower-mass and higher-redshift clusters, and thermal noise alone sets how many halos can be found.

What would settle it

A completed SKA-Low AA4 survey of southern SZ/X-ray clusters that yields substantially fewer than ~2500 radio-halo detections (or far fewer than ~1000 ultra-steep systems) up to z≈0.6, after careful source subtraction, would contradict the forecast.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • SKA-Low will give the first statistically meaningful census of radio halos and ultra-steep-spectrum halos at z>0.6.
  • Halos will become detectable in clusters an order of magnitude less massive than those routinely studied today.
  • The observed fraction of ultra-steep versus flat-spectrum halos as a function of mass and redshift will directly test whether turbulence efficiency scales as the models assume.
  • Joint SKA-Low + SKA-Mid imaging will separate diffuse emission from embedded galaxies, enabling clean spectral-index maps of high-redshift systems.

Where Pith is reading between the lines

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

  • If the predicted ultra-steep population is confirmed, magnetic-field amplification and particle re-acceleration must already be efficient when the Universe was only 5–7 Gyr old.
  • A large sample of low-mass, high-z halos would open a new route to map the non-thermal energy budget of the cosmic web itself, not only the densest cluster cores.
  • Discrepancies between the forecast and the eventual SKA counts would most naturally point to spatially patchy turbulence or evolving magnetic-field strengths rather than a wholesale failure of re-acceleration.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

2 major / 5 minor

Summary. The chapter models giant radio-halo formation under the turbulent re-acceleration scenario with Monte Carlo merger trees (extended Press–Schechter) calibrated to LoTSS-DR2 occurrence, flux and mass trends, and the Cuciti et al. (2023) P_150–M_500 relation. Homogeneous-model parameters (⟨B⟩ = 2 μG, η_t = 0.2, R_H ≃ 400 kpc) are adopted. Detection thresholds are set by the analytic minimum-flux formula (Eq. 1) with SKA-Low AA4 thermal-noise values (F_rms ≃ 20 μJy beam^{-1}, θ_b = 10″). Integrating the resulting radio-halo luminosity function (Eqs. 2–4) yields the headline prediction that SKA-Low will detect at least ∼2500 (up to ∼2600) radio halos to z ≃ 0.6, of which ≳1000 are ultra-steep-spectrum systems, and will reach clusters down to ∼10^{14} M_⊙ and out to z ≃ 1, thereby testing re-acceleration models over an unprecedented mass–redshift range.

Significance. If the yield and spectral-mix forecasts hold, SKA-Low AA4 will enlarge the known radio-halo sample by more than an order of magnitude relative to LoTSS, open the low-mass and high-redshift regimes, and supply a statistically decisive test of the ultra-steep-spectrum population that is a distinctive prediction of turbulent re-acceleration. The Monte Carlo machinery is standard, has already been shown to reproduce LoTSS-DR2 number counts and mass trends, and the detection-threshold formula is transparent and matches existing upper limits. The work therefore supplies concrete, falsifiable survey forecasts that are of clear value for SKA science planning and for the non-thermal cluster community.

major comments (2)
  1. Abstract and §6 present the integrated yield as “at least ∼2500” / “up to ∼2600” radio halos to z ≃ 0.6. The integral (Eq. 4) is performed down to the pure thermal-noise P_min(z) of Eq. 1 with F_rms = 20 μJy beam^{-1}. The manuscript itself states that this sensitivity is already confusion-limited (Braun 2014; Braun et al. 2019) and that residual compact/extended galaxy emission, calibration artefacts and surface-brightness limits will reduce completeness, especially for low-surface-brightness USSRH and high-z systems (§4, §7.2). Because the bulk of the predicted gain lies near the detection threshold (low-mass, steep-spectrum end of the RHLF), an unquantified completeness factor of even ∼0.5 would move the absolute number well below the advertised floor. The qualitative expansion of discovery space remains robust, but the absolute numbers should be re-framed as optimistic thermal-noise
  2. §5 and §6 adopt a single homogeneous-model parameter set (⟨B⟩ = 2 μG, η_t = 0.2, R_H ≃ 400 kpc) plus the observed P_150–M_500 relation (scatter 0.4 dex) across the full mass and redshift range that SKA will probe (down to ∼10^{14} M_⊙ and out to z ∼ 1). While the text asserts that “general conclusions remain robust against reasonable variations,” no quantitative sensitivity of the ∼2500 / ≳1000 USSRH yields to these parameters (or to the slope/normalisation of the P–M relation) is shown. A short table or set of curves varying η_t, ⟨B⟩ and the P–M slope within the currently allowed range would make the load-bearing claim that the discovery-space gain is robust fully transparent.
minor comments (5)
  1. Eq. 1 and the surrounding text switch between 2 heta_e and 3 heta_e; a single consistent definition of the aperture used for detection would improve clarity.
  2. Fig. 2 caption and panel labels mix “blu line” / “blue line” and give parameters only in the figure; a short table of the exact F_rms, heta_b and heta_e assumptions used for LoTSS versus SKA-Low would help the reader reproduce the curves.
  3. Author affiliations are numbered non-sequentially (1,2,3,1,3,10,…); renumber for readability.
  4. A few typographical slips remain (e.g. “Giantradiohalos”, “InthisChapter”, missing spaces after periods). A light copy-edit pass is warranted.
  5. §7.2 notes that the quoted counts are optimistic and that SKA-Mid will be needed for source subtraction; a cross-reference back to the abstract/headline numbers would make the caveat more visible to readers who stop at the abstract.

Circularity Check

1 steps flagged

Ordinary calibration of Monte Carlo re-acceleration model to LoTSS-DR2 + Cuciti P–M relation, then extrapolated to independent SKA-Low thermal-noise threshold; no tautological reduction of the ~2500 yield.

specific steps
  1. fitted input called prediction [§5 (model parameters) + §5.2 (RHLF) + §6 (Eq. 4)]
    "we adopt a reference set of parameters—⟨B⟩=2μG … η_t=0.2, and R_H≃400 kpc—which has been shown to reproduce the observed RH statistics … Most notably, this model successfully reproduces the statistical properties of RHs observed in the LoTSS-DR2 survey … The number of RHs … can be calculated by integrating the RHLF (Eq. 2) … We estimate that SKA1-Low could be able to detect up to ∼2600 out to z∼0.6"

    The three free parameters and the P–M normalisation/slope are fixed to LoTSS-DR2 (and earlier) data by the same group; the SKA count is then obtained by feeding those fitted values into the identical RHLF and integrating to a new (but still model-dependent) flux limit. The absolute number therefore inherits the calibration, yet the SKA threshold and redshift baseline remain independent, so the step is only mildly circular (ordinary forecast practice) rather than tautological.

full rationale

The paper explicitly adopts a previously published homogeneous turbulent re-acceleration Monte Carlo framework (Cassano & Brunetti 2005; Cassano et al. 2006 et seq.), fixes its three free parameters (⟨B⟩=2 μG, η_t=0.2, R_H≃400 kpc) so that the model reproduces LoTSS-DR2 occurrence, flux and mass distributions, inserts the observed Cuciti et al. (2023) P_150–M_500 relation (with its measured 0.4 dex scatter) into the RHLF (Eq. 2), and integrates that RHLF down to the SKA-Low thermal-noise P_min(z) given by Eq. 1 with F_rms=20 μJy beam^{-1}. The SKA sensitivity, resolution and southern-sky cluster catalogue are independent inputs; the absolute number ~2500 (and the USSRH fraction) is therefore a genuine forecast, not a quantity forced by construction from the calibration data. Heavy self-citation of the authors’ earlier Monte Carlo papers is present but is the normal scaffolding of a multi-paper modelling programme; it does not collapse the SKA prediction into a re-statement of the LoTSS fit. Completeness losses from confusion and residual galaxy emission are flagged by the paper itself and affect the absolute yield, but that is a systematic uncertainty, not circularity. Score 2 reflects only the mild, non-load-bearing self-citation of the calibration step.

Axiom & Free-Parameter Ledger

4 free parameters · 4 axioms · 0 invented entities

The central numerical claim rests on a small set of free parameters fixed by earlier LOFAR/uGMRT statistics, on the standard turbulent re-acceleration scenario, and on the Press–Schechter merger trees. No new physical entities are invented; the work is an application of an established framework.

free parameters (4)
  • η_t (turbulent energy fraction) = 0.2
    Fraction of PdV work converted into turbulence; set to 0.2 to match LoTSS statistics (§5).
  • ⟨B⟩ (mean magnetic field) = 2 μG
    Volume-averaged field strength inside the halo; fixed at 2 μG consistent with Bonafede et al. (2010) and prior model calibrations (§5).
  • R_H (typical halo radius) = ≃400 kpc
    Assumed emitting radius; set to ≃400 kpc (§5).
  • A, B of P_150–M_500 relation = A=1.1±0.1, B=3.59±0.48
    Normalization and slope of the radio power–mass correlation taken from Cuciti et al. (2023) with 0.4 dex scatter; used to convert mass functions into luminosity functions (Eq. 3).
axioms (4)
  • domain assumption Turbulent re-acceleration of pre-existing relativistic electrons by merger-driven turbulence is the dominant mechanism producing giant radio halos.
    Adopted throughout §1 and §5; secondary hadronic contribution is stated to be sub-dominant for classical halos.
  • domain assumption Extended Press–Schechter formalism correctly supplies the statistical merger trees of dark-matter halos.
    Used to generate the Monte Carlo cluster histories (§5).
  • ad hoc to paper Only halos with spectral steepening frequency ν_s ≥ observing frequency are detectable; homogeneous models (constant turbulence, B, acceleration rate inside R_H) suffice for statistical predictions.
    Explicit modelling choices in §5 that simplify the calculation of occurrence and luminosity functions.
  • standard math ΛCDM cosmology with H_0=70, Ω_m=0.3, Ω_Λ=0.7.
    Stated at end of §1; standard background.

reviewed 2026-07-14 · how reviews work

0 comments
Cite this review

Pith. "Pith review of Radio Halos in Galaxy Clusters as unveiled by the SKA telescope." pith.science (2026). https://pith.science/paper/NWGALP75

@misc{pith2026260710304,
  author       = {Pith},
  title        = {Pith review of: Radio Halos in Galaxy Clusters as unveiled by the SKA telescope},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/NWGALP75}},
  note         = {Machine review of arXiv:2607.10304}
}
Share X Bluesky LinkedIn Reddit HN
abstract

Giant radio halos (RHs) are diffuse, Mpc-scale synchrotron sources observed in a growing fraction of galaxy clusters. They trace relativistic particles and magnetic fields in the intracluster medium (ICM), providing a unique window into non-thermal processes and their role in cluster evolution. RHs are primarily found in merging systems, supporting models in which turbulence generated during cluster collisions re-accelerates pre-existing electrons to the energies required for the observed radio emission. In this scenario, the occurrence, power, and spectral properties of RHs depend on the energetics of cluster mergers, with the most massive and dynamically disturbed clusters hosting the most powerful halos. Low-frequency observations are crucial to uncover ultra-steep-spectrum RHs, a key prediction of turbulent re-acceleration models, and are expected to arise from less energetic merger events. LOFAR has enabled statistical studies of large cluster samples, placing robust constraints on RH occurrence and spectral trends. In this Chapter, we model RH formation and evolution using Monte Carlo simulations calibrated on LoTSS-DR2 findings, and we present predictions for SKA-Low in the AA4 configuration. Our results show that SKA will probe an unprecedented region of cluster mass and redshift space, detecting at least $\sim 2500$ RHs up to $z \approx 0.6$, including $\gtrsim 1000$ ultra-steep-spectrum systems, and revealing halos in clusters down to $\sim 10^{14}\, M_\odot$ and out to $z \approx 1$. These surveys will provide stringent tests of turbulent re-acceleration models and significantly advance our understanding of non-thermal processes in galaxy clusters.

Figures

Figures reproduced from arXiv: 2607.10304 by A. Bonafede, A. Botteon, A. Datta, C. Giocoli, F. Gastaldello, G. Bernardi, G. Brunetti, G. Di Gennaro, G. W. Pratt, H. J. A. R\"ottgering, K. Dolag, K. S. L. Srikanth, M. Balboni, M. Br\"uggen, M. Gitti, M. Pandey-Pommier, M. Rahaman, M. Rossetti, R. Cassano, R. J. van Weeren, R. Kale, R. Santra, S. Chatterjee, S. Ettori, S. Giacintucci, T. Venturi, V. Cuciti.

Figure 1
Figure 1. Figure 1: The radio halo in the galaxy cluster Abell 2255 observed with different radio facilities. enhanced synchrotron emission within the intracluster medium (ICM). Such features, typically a few to tens of kpc wide and extending up to several hundred kpc, have been detected in numerous systems, including Abell 3667, RXC J1825.3+3026, and several MGCLS clusters (Knowles et al., 2022; Riseley et al., 2022; Botteon… view at source ↗
Figure 2
Figure 2. Figure 2: Radio power of halos and detection thresholds as a function of redshift. The corresponding minimum radio power 𝑃min (𝑧) is reported in [PITH_FULL_IMAGE:figures/full_fig_p008_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Model expectations at 150 MHz from (Cassano et al., 2023). dropping to ∼40% for clusters with 𝑀𝑣 ∼ 1.4 × 1015, 𝑀⊙ (𝑀500 ∼ 7 × 1014 M⊙). At higher redshifts, the predicted fraction of USSRH rises for clusters of similar mass, reflecting stronger inverse Compton losses and the evolving merger rate. 5.2 The radio halo luminosity function The luminosity functions of radio halos (RHLFs) with 𝜈𝑠 ≥ 𝜈0 (i.e. the e… view at source ↗
Figure 4
Figure 4. Figure 4: Distribution of galaxy groups and clusters in the mass–redshift plane from current X-ray and SZ surveys (e.g. PSZ, eROSITA, SPT, ACT). Lines define for each redshift the minimum mass of clusters that will be efficiently probed by SKA-Low in its AA4 configuration (solid line) and by LoTSS-DR2 (dashed line). Compact Telescope (ACT; Calabrese et al., 2025; Aguena et al., 2026), the South Pole Telescope (SPT; … view at source ↗

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

71 extracted references · 7 canonical work pages · 3 internal anchors

  1. [1]

    doi: 10.1051/0004-6361/201526920. R. Adam et al.A&A, 648:A60, Apr

    doi:10.1051/0004-6361/201526920

  2. [2]

    doi: 10.1051/0004-6361/202039660. M. Aguena et al.The Open Journal of Astrophysics, 9:55863, Jan

    doi:10.1051/0004-6361/202039660

  3. [3]

    doi: 10.33232/001c. 155863. M. Balboni et al.A&A, 686:A5, June

    doi:10.33232/001c

  4. [4]

    doi: 10.1051/0004-6361/202347965. M. Balboni et al.A&A, 695:A180, Mar. 2025a. doi: 10.1051/0004-6361/202453183. M. Balboni et al.arXiv e-prints, art. arXiv:2507.00133, June 2025b. doi: 10.48550/arXiv.2507. 00133. P. Blasi and S. Colafrancesco.Astroparticle Physics, 12(3):169–183, Nov

    doi:10.1051/0004-6361/202347965

  5. [5]

    doi: 10.3847/1538-4357/ab1f10. A. Bonafede et al.A&A, 513:A30, Apr

    doi:10.3847/1538-4357/ab1f10

  6. [6]

    doi: 10.1051/0004-6361/200913696. A. Bonafede et al.MNRAS, 444:L44–L48, Oct

    doi:10.1051/0004-6361/200913696

  7. [7]

    doi: 10.1093/mnrasl/slu110. A. Botteon et al.MNRAS, 478(1):885–898, July

    doi:10.1093/mnrasl/slu110

  8. [8]

    15 Radio Halos Cassano et al

    doi: 10.1093/mnras/sty1102. 15 Radio Halos Cassano et al. A. Botteon et al.APJ, 897(1):93, July

    doi:10.1093/mnras/sty1102

  9. [9]

    doi: 10.3847/1538-4357/ab9a2f. A. Botteon et al.ApJL, 914(2):L29, June

    doi:10.3847/1538-4357/ab9a2f

  10. [10]

    doi: 10.3847/2041-8213/ac0636. A. Botteon et al.A&A, 660:A78, Apr. 2022a. doi: 10.1051/0004-6361/202143020. A. Botteon et al.Science Advances, 8(44):eabq7623, Nov. 2022b. doi: 10.1126/sciadv.abq7623. A. Botteon et al.A&A, 674:A53, June

    doi:10.3847/2041-8213/ac0636 2041

  11. [11]

    doi: 10.1051/0004-6361/202346150. A. Botteon et al.A&A, 690:A222, Oct

    doi:10.1051/0004-6361/202346150

  12. [12]

    doi: 10.1051/0004-6361/202451293. A. Botteon et al.A&A, 698:A55, June

    doi:10.1051/0004-6361/202451293

  13. [13]

    doi: 10.1051/0004-6361/202554695. R.Braun. Ska1imagingscienceperformance. TechnicalReportSKA-TEL-SKO-DD-XXX,Rev.A Draft 2, SKA Organisation,

    doi:10.1051/0004-6361/202554695

  14. [14]

    Technical re- port

    URLhttps://indico.skatelescope.org/event/270/ attachments/1919/2406/SKA1_Science_PerformanceRevA_draft2.pdf. Technical re- port. R.Braunandetal.ProceedingsoftheInternationalAstronomicalUnion,15:362–365,2019. SKA1 survey sensitivity and capabilities. S. Brown, A. Emerick, L. Rudnick, and G. Brunetti.ApJL, 740(1):L28, Oct

    1919

  15. [15]

    doi: 10.1088/ 2041-8205/740/1/L28. G. Brunetti and T. W. Jones.International Journal of Modern Physics D, 23(4):1430007-98, Mar

    2041

  16. [16]

    G.BrunettiandA.Lazarian.MNRAS,410(1):127–142,Jan.2011

    doi: 10.1142/S0218271814300079. G.BrunettiandA.Lazarian.MNRAS,410(1):127–142,Jan.2011. doi: 10.1111/j.1365-2966.2010. 17457.x. G.BrunettiandA.Lazarian.MNRAS,458(3):2584–2595,May2016. doi: 10.1093/mnras/stw496. G. Brunetti and F. Vazza.Physical Review Letter, 124(5):051101, Feb

    doi:10.1142/s0218271814300079 2011

  17. [17]

    doi: 10.1016/S1384-1076(00)00048-8. G. Brunetti et al.Nature, 455(7215):944–947, Oct

    work page doi:10.1016/s1384-1076(00)00048-8

  18. [18]

    doi: 10.1038/nature07379. G. Brunetti, S. Zimmer, and F. Zandanel.MNRAS, 472(2):1506–1525, Dec

    doi:10.1038/nature07379

  19. [19]

    doi: 10.1051/0004-6361/202039877. E. Bulbul et al.A&A, 685:A106, May

    doi:10.1051/0004-6361/202039877

  20. [20]

    doi: 10.1051/0004-6361/202348264. E. Calabrese et al.arXiv e-prints, art. arXiv:2503.14454, Mar

    Pith/arXiv arXiv doi:10.1051/0004-6361/202348264

  21. [21]

    doi: 10.48550/arXiv.2503. 14454. R. Cassano and G. Brunetti.MNRAS, 357(4):1313–1329, Mar

    doi:10.48550/arxiv.2503

  22. [23]

    Some useful approximations for calculation of directivities of multibeam power patterns of large planar arrays

    doi: 10.1111/j.1365-2966. 2006.10423.x. R. Cassano, G. Brunetti, and G. Setti.MNRAS, 369(4):1577–1595, July

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1111/j.1365-2966 2006

  23. [24]

    1365-2966.2006.10423.x

    doi: 10.1111/j. 1365-2966.2006.10423.x. R. Cassano et al.A&A, 480(3):687–697, Mar

    doi:10.1111/j 2006

  24. [25]

    doi: 10.1051/0004-6361:20078986. R. Cassano, G. Brunetti, H. J. A. Röttgering, and M. Brüggen.A&A, 509:A68, Jan

    doi:10.1051/0004-6361:20078986

  25. [26]

    doi: 10.1051/0004-6361/200913063. R. Cassano et al.A&A, 548:A100, Dec

    work page doi:10.1051/0004-6361/200913063

  26. [27]

    doi: 10.1051/0004-6361/201220018. R. Cassano et al.APJ, 777(2):141, Nov

    doi:10.1051/0004-6361/201220018

  27. [28]

    R.Cassanoetal

    doi: 10.1088/0004-637X/777/2/141. R.Cassanoetal. InAdvancingAstrophysicswiththeSquareKilometreArray(AASKA14),page73, 16 Radio Halos Cassano et al. Apr

    doi:10.1088/0004-637x/777/2/141

  28. [29]

    doi: 10.22323/1.215.0073. R. Cassano et al.ApJL, 881(1):L18, Aug

    doi:10.22323/1.215.0073

  29. [30]

    doi: 10.3847/2041-8213/ab32ed. R. Cassano et al.A&A, 672:A43, Apr

    doi:10.3847/2041-8213/ab32ed 2041

  30. [31]

    doi: 10.1051/0004-6361/202244876. R. Cassano et al.Astronomy and Astrophysics, 672, 4

    doi:10.1051/0004-6361/202244876

  31. [33]

    doi: 10.1051/0004-6361/201526420. V. Cuciti et al.A&A, 647:A51, Mar

    doi:10.1051/0004-6361/201526420

  32. [34]

    doi: 10.1051/0004-6361/202039208. V. Cuciti et al.Nature, 609(7929):911–914, Sept

    doi:10.1051/0004-6361/202039208

  33. [35]

    doi: 10.1038/s41586-022-05149-3. V. Cuciti et al.A&A, 680:A30, Dec

    doi:10.1038/s41586-022-05149-3

  34. [36]

    V.Cucitietal

    doi: 10.1051/0004-6361/202346755. V.Cucitietal. InAdvancingAstrophysicswiththeSKA–II(AASKAII).2026. arXivsearch: Report number AASKAII/Cuciti01. D. Dallacasa et al.APJ, 699(2):1288–1292, July

    doi:10.1051/0004-6361/202346755 2026

  35. [37]

    doi: 10.1088/0004-637X/699/2/1288. F. de Gasperin et al.A&A, 659:A146, Mar

    doi:10.1088/0004-637x/699/2/1288

  36. [38]

    doi: 10.1051/0004-6361/202142658. B. Dennison.ApJL, 239:L93–L96, Aug

    doi:10.1051/0004-6361/202142658

  37. [39]

    G.DiGennaroetal.NatureAstronomy,5:268–275,Jan.2021a.doi: 10.1038/s41550-020-01244-5

    doi: 10.1086/183300. G.DiGennaroetal.NatureAstronomy,5:268–275,Jan.2021a.doi: 10.1038/s41550-020-01244-5. G. Di Gennaro et al.A&A, 654:A166, Oct. 2021b. doi: 10.1051/0004-6361/202141510. G. Di Gennaro et al.A&A, 695:A215, Mar

    doi:10.1086/183300

  38. [40]

    doi: 10.1051/0004-6361/202453203. J. Donnert, K. Dolag, G. Brunetti, and R. Cassano.MNRAS, 429:3564–3569, Mar

    doi:10.1051/0004-6361/202453203

  39. [41]

    doi: 10.1093/mnras/sts628. S. W. Duchesne, M. Johnston-Hollitt, and I. Bartalucci.PASA, 38:e053, Oct

    doi:10.1093/mnras/sts628

  40. [42]

    Euclid Collaboration et al.A&A, 662:A112, June

    doi: 10.1017/ pasa.2021.45. Euclid Collaboration et al.A&A, 662:A112, June

    2021

  41. [43]

    doi: 10.1051/0004-6361/202141938. L. Feretti, H. Boehringer, G. Giovannini, and D. Neumann.A&A, 317:432–440, Jan

    doi:10.1051/0004-6361/202141938

  42. [44]

    doi: 10.48550/arXiv.astro-ph/9607027. L. Feretti, G. Giovannini, F. Govoni, and M. Murgia.A&ARv, 20:54, May

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.astro-ph/9607027

  43. [45]

    Y.Fujita, M.Takizawa, andC.L.Sarazin.APJ,584(1):190–202, Feb.2003

    doi: 10.1007/ s00159-012-0054-z. Y.Fujita, M.Takizawa, andC.L.Sarazin.APJ,584(1):190–202, Feb.2003. doi: 10.1086/345599. A. H. Gonzalez et al.ApJSS, 240(2):33, Feb

    work page doi:10.1086/345599 2003

  44. [46]

    doi: 10.3847/1538-4365/aafad2. F. Govoni et al.Science, 364(6444):981–984, June

    doi:10.3847/1538-4365/aafad2

  45. [47]

    doi: 10.1126/science.aat7500. E. J. Hallman et al.ApJ, 731:L18,

    doi:10.1126/science.aat7500

  46. [48]

    doi: 10.1088/2041-8205/731/1/L18. J. HLavacek-Larrondo et al.ApJL, 987(2):L40, July

    work page doi:10.1088/2041-8205/731/1/l18 2041

  47. [49]

    doi: 10.3847/2041-8213/add527. Y. Hu et al.Nature Communications, 15:1006, Feb

    doi:10.3847/2041-8213/add527 2041

  48. [50]

    K.HyeongHanetal.NatureAstronomy,9:925–931,June2025.doi: 10.1038/s41550-025-02530-w

    doi: 10.1038/s41467-024-45164-8. K.HyeongHanetal.NatureAstronomy,9:925–931,June2025.doi: 10.1038/s41550-025-02530-w. R. Kale et al.A&A, 579:A92, July

    doi:10.1038/s41467-024-45164-8

  49. [51]

    R.Kale,K.M.Shende,andV.Parekh.MNRAS,486(1):L80–L84,June2019

    doi: 10.1051/0004-6361/201525695. R.Kale,K.M.Shende,andV.Parekh.MNRAS,486(1):L80–L84,June2019. doi: 10.1093/mnrasl/ slz061. K. Knowles et al.A&A, 657:A56, Jan

    doi:10.1051/0004-6361/201525695

  50. [52]

    doi: 10.1051/0004-6361/202141488. C. Lacey and S. Cole.MNRAS, 262(3):627–649, June

    doi:10.1051/0004-6361/202141488

  51. [53]

    doi: 10.1093/mnras/262.3.627. G. Macario et al.A&A, 551:A141, Mar

    doi:10.1093/mnras/262.3.627

  52. [54]

    Discovery of a $z \sim 0.8$ Ultra Steep Spectrum Radio Halo in the MeerKAT-South Pole Telescope Survey

    doi: 10.1051/0004-6361/201220667. I.S.Magolegoetal.arXive-prints,art.arXiv:2509.08062,Sept.2025. doi: 10.48550/arXiv.2509. 08062. 17 Radio Halos Cassano et al. A. Pagliotta et al.A&A, 700:A139, Aug

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201220667 2025

  53. [55]

    doi: 10.1051/0004-6361/202554881. V. Petrosian.APJ, 557:560–572, Aug

    doi:10.1051/0004-6361/202554881

  54. [56]

    doi: 10.1086/321557. D. G. Phuravhathu et al.MNRAS, 542(2):1544–1561, Sept

    doi:10.1086/321557

  55. [57]

    doi: 10.1093/mnras/staf1315. S. Pinjarkar et al.MNRAS, 537(4):3481–3498, Mar

    doi:10.1093/mnras/staf1315

  56. [58]

    doi: 10.1093/mnras/staf209. R. F. Pizzo and A. G. de Bruyn.A&A, 507(2):639–659, Nov

    doi:10.1093/mnras/staf209

  57. [60]

    doi: 10.1051/0004-6361/202244925. K. e. a. Rajpurohit.Astronomy & Astrophysics, 655:A30,

    doi:10.1051/0004-6361/202244925

  58. [61]

    doi: 10.1051/0004-6361/ 202141499. C. J. Riseley et al.MNRAS, 515(2):1871–1896, Sept

    doi:10.1051/0004-6361/

  59. [62]

    doi: 10.1093/mnras/stac1771. R. Santra et al.APJ, 962(1):40, Feb

    doi:10.1093/mnras/stac1771

  60. [63]

    doi: 10.3847/1538-4357/ad1190. F. Savini et al.MNRAS, 478(2):2234–2242, Aug

    doi:10.3847/1538-4357/ad1190

  61. [64]

    doi: 10.1093/mnras/sty1125. T. W. Shimwell et al.A&A, 598:A104, Feb

    doi:10.1093/mnras/sty1125

  62. [65]

    doi: 10.1051/0004-6361/201629313. T. W. Shimwell et al.A&A, 622:A1, Feb

    doi:10.1051/0004-6361/201629313

  63. [66]

    doi: 10.1051/0004-6361/201833559. T. W. Shimwell et al.A&A, 659:A1, Mar

    doi:10.1051/0004-6361/201833559

  64. [67]

    doi: 10.1051/0004-6361/202142484. S. P. Sikhosana et al.A&A, 698:L17, June

    doi:10.1051/0004-6361/202142484

  65. [68]

    doi: 10.1051/0004-6361/202453410. C. Tasse et al.A&A, 648:A1, Apr

    doi:10.1051/0004-6361/202453410

  66. [69]

    doi: 10.1051/0004-6361/202038804. R. J. van Weeren et al.Space Sci. Rev., 215(1):16, Feb

    doi:10.1051/0004-6361/202038804

  67. [70]

    doi: 10.1007/s11214-019-0584-z. R. J. van Weeren et al.A&A, 692:A12, Dec

    doi:10.1007/s11214-019-0584-z

  68. [71]

    doi: 10.1051/0004-6361/202451618. F. Vazza and G. Brunetti.arXiv e-prints, art. arXiv:2507.04727, July

    doi:10.1051/0004-6361/202451618

  69. [72]

    2507.04727

    doi: 10.48550/arXiv. 2507.04727. F. Vazza et al.MNRAS, 369(1):L14–L18, June

    doi:10.48550/arxiv

  70. [73]

    doi: 10.1111/j.1745-3933.2006.00164.x. A. Wilber et al.MNRAS, 473(3):3536–3546, Jan

    doi:10.1111/j.1745-3933.2006.00164.x 2006

  71. [74]

    XRISM Collaboration et al.arXiv e-prints, art

    doi: 10.1093/mnras/stx2568. XRISM Collaboration et al.arXiv e-prints, art. arXiv:2508.05067, Aug. 2025a. doi: 10.48550/ arXiv.2508.05067. XRISM Collaboration et al.arXiv e-prints, art. arXiv:2509.04421, Sept. 2025b. doi: 10.48550/ arXiv.2509.04421. XRISM Collaboration et al.ApJL, 982(1):L5, Mar. 2025c. doi: 10.3847/2041-8213/ada7cd. 18

    Pith/arXiv arXiv doi:10.1093/mnras/stx2568 2041

This paper was first reviewed by grok-4.5 on July 14, 2026.