{"id":"e9361c2c-2c88-46fe-98f5-60428cb7ff58","arxiv_id":"2607.06664","paper_version":1,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"For a low-mass CCSN progenitor, rotation alone weakly and non-monotonically affects explosion energy and observables; only the fastest spin yields T/|W| spiral modes and spin-kick alignment, with core spin amplified by ~4000.","lead":"3D simulations of a 9-solar-mass star show that pure rotation (no magnetic fields) barely changes explosion energy, kicks, or nucleosynthesis across a wide spin range. Only the fastest rotator develops spiral-arm instabilities and clear spin-kick alignment, implying most real cores start spinning slowly.","discovery_kind":"extension","skeptic_critique":{"model":"grok-4.5","headline":"No significant objection beyond the single-progenitor scope already flagged by the reader; the scoped claim holds under the paper's own caveats.","rationale":"The reader correctly isolates the single-progenitor + no-B-field + ad-hoc spin-law premise as the weakest link for any broader claim, while accepting the carefully caveated result for the 9-M⊙ model. My re-examination of the hydro, neutrino, kick, nucleosynthesis, and GW sections finds no additional load-bearing flaw: the non-monotonic energy trend is explained by the competing centrifugal-support versus reduced-heating effects (§3–4), the ~4000 spin-up factor follows directly from Table 1, and the T/|W| modes are reported only for the fastest rotator with appropriate Nyquist caveats. Because the paper already states the limitation and the reader’s CONDITIONAL verdict already requires multi-progenitor confirmation before treating the “most cores” language as settled, no further adjustment is warranted.","tokens_in":26409,"tokens_out":558,"duration_ms":6543,"concrete_test":"Re-run the identical Fornax setup (SFHo, 12 energy groups, 1024\times128\times256 dendritic grid) for one higher-compactness progenitor (e.g., Sukhbold 15–20 M⊙) at the same four Ω0 values; if explosion energy, shock dipole, and heating rates remain within ~20 % of the non-rotating case except at Ω0=1, the muted-effect claim strengthens; if qualitative changes appear already at Ω0=0.1, the “most cores” implication fails.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The paper's strongest claim is carefully scoped to one early-exploding 9-M⊙ progenitor under pure hydrodynamics with the Eriguchi–Müller cylindrical law (A=1000 km). Within that scope the four runs (Table 1, Figs. 1, 9–11, 17–19) show only weak, non-monotonic dependence of explosion energy, shock asymmetry, neutrino heating, and yields on spin, with T/|W|~0.05 spiral modes and spin-kick alignment appearing solely for Ω0=1 rad s−1. The generalization language (“most supernova cores,” “muted consequences \times most of the time”) is already caveated in §9 and the abstract. No internal inconsistency, hidden assumption, or numerical artifact undermines the reported trends for this model; the load-bearing limitation is precisely the single-progenitor, no-B-field restriction already identified by the reader.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.5","summary":"The paper presents four long-term 3D multi-group radiation-hydrodynamics simulations (Fornax, SFHo EOS, 12 energy groups) of the Sukhbold et al. (2016) 9-M⊙ progenitor, varying only the initial central angular frequency Ω0 = 0, 0.01, 0.1, and 1.0 rad s−1 under the Eriguchi & Müller cylindrical rotation law (A = 1000 km) and deliberately omitting magnetic fields. The runs are carried to asymptotic saturation of explosion energy, residual mass, kicks, nucleosynthesis, and gravitational-wave emission. The central claim is that, for this early-exploding low-mass model, rotation alone produces only weak, non-monotonic changes (≲20 %) in explosion energy, modest increases in blast asymmetry, negligible pole–equator heating anisotropy during the launch phase, and little change in yields; only the fastest rotator develops a T/|W| ≈ 0.05 corotation instability with spiral arms, stronger GW emission, and clear spin–kick alignment, while the initial-to-final core spin-period ratio is measured to be ∼4000.","tokens_in":26632,"tokens_out":1092,"duration_ms":29320,"significance":"If the reported trends hold, the work supplies a clean, systematically varied benchmark isolating pure hydrodynamic rotational effects for an early-exploding progenitor. The long-term (≳2 s) multi-messenger diagnostics—explosion energy, residual mass, recoil kicks, Ye–entropy distributions, production factors, and both matter and neutrino GW spectrograms—are valuable for the community. The clear detection of low-T/|W| spiral modes and the measured spin amplification factor ∼4000 are concrete, falsifiable results that constrain progenitor spin models and GW templates. The careful scoping to one low-compactness progenitor and the explicit omission of magnetic fields are strengths of scientific honesty rather than weaknesses.","major_comments":[{"comment":"Table 1 and §3: the final spin periods (and therefore the quoted initial-to-final ratio ∼4000) are obtained from L/I_NS with the spherical Breu & Rezzolla (2016) formula and a fixed R_NS = 12 km. For the Ω0 = 1 model (T/|W| ≈ 0.0475 at 2 s) the spherical approximation underestimates the true moment of inertia; a short quantification of the resulting period error (or a non-spherical I estimate) is needed before the ratio is used to infer that “most supernova cores” are born slowly rotating.","section":"Table 1, §3"},{"comment":"§2 and §9: the Eriguchi & Müller cylindrical law with fixed scale A = 1000 km is adopted without a sensitivity test. Because the paper’s strongest claim is that rotation effects remain muted “across a wide range of initial spins,” at least a brief discussion (or one additional run) of how changing A by a factor of a few alters the early gain-region centrifugal support and the final T/|W| would strengthen the robustness of that claim.","section":"§2, §9"}],"minor_comments":[{"comment":"Abstract and §3: “a T/|W| corotation instabilities” is grammatically incorrect; change to “a T/|W| corotation instability” or “T/|W| corotation instabilities.”","section":"Abstract, §3"},{"comment":"Figure 1 caption and several places in the text use inconsistent spacing (“T /|W|”, “T/|W|”); standardize to T/|W|.","section":"Figure 1, §3, §8"},{"comment":"§1: “motive this work” should be “motivate this work.”","section":"§1"},{"comment":"Figure 9 and text: model labels occasionally appear as “9-rot0.0” or “9-rot0.1” without the hyphen; keep the consistent “9-rot-0.0” form used in Table 1.","section":"Figure 9, §4"},{"comment":"§8: the statement that the hydro dump cadence is 1000 Hz (Nyquist-limited to 500 Hz) while GW data are written at 25–50 kHz is useful; a single sentence noting that a higher hydro cadence will be required for a full modal decomposition of the spiral arms would help the reader.","section":"§8"}],"recommendation":"minor_revision","confidential_remarks":"The manuscript is a solid, carefully scoped contribution that already contains the necessary caveats. The two major points are easily addressable and do not threaten the central claim. I see no reason for a second full review cycle if the authors supply the short I_NS quantification and a brief A-sensitivity discussion."},"author_rebuttal":null,"desk_editor":{"model":"grok-4.5","letter":"This is a clean parameter study that actually answers a practical question: how much does pure rotation change the late-time observables for a low-mass, early-exploding core? The answer, for the Sukhbold 9 M☉ model run with Fornax to saturation, is “not much” until you hit Ω0 = 1 rad s−1.\n\nWhat is new is the controlled continuum (0, 0.01, 0.1, 1.0 rad s−1) carried all the way to asymptotic energy, kicks, yields, and GW, rather than stopping at early explodability. Energy is non-monotonic and stays within ~20 %. Neutrino luminosities and heating barely move except for the fastest model, and even then the early heating anisotropy is weak because the star explodes before the PNS has spun up and become strongly oblate. Spin-kick alignment and clear multi-m spiral arms at T/|W| ~ 0.05 appear only for that fastest run; the GW spectrograms make the modes obvious. The measured initial-to-final period ratio ~4000 is a useful number for the pulsar-birth discussion. Methods, grid, EOS, and neutrino groups are standard Fornax and the trends look internally consistent.\n\nThe soft spots are exactly the ones the authors flag: one progenitor, no magnetic fields, and the usual Eriguchi–Müller cylindrical law with fixed A = 1000 km. The abstract and §9 already say the generalization to “most cores” is provisional. That is not a hidden flaw; it is the natural limit of a four-run study. Data and code are not public, which is normal for this group but still a practical friction.\n\nAnyone working on CCSN systematics, pulsar birth spins, or GW from rotating cores will get value from the tables and figures. It is not a mechanism paper and does not reorganize the field, but it is honest computational work that fills a real gap. I would send it to referees without hesitation; the scoped claim holds and the caveats are already written.","headline":"Solid, carefully scoped Fornax continuum: pure rotation is muted for this early-exploding 9 M☉ model except at the fastest spin, where T/|W| spirals and spin-kick alignment appear.","tokens_in":27307,"tokens_out":576,"would_cite":true,"duration_ms":7184,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.5","headline":"Rotation alone barely changes explosion energy, blast shape, or yields for a low-mass supernova that explodes early.","keywords":["core-collapse supernovae","rotation","3D simulations","explosion energy","spin-kick alignment","T/|W| instability","gravitational waves","nucleosynthesis"],"falsifier":"Repeat the same rotation sequence for a higher-compactness progenitor that explodes later; if that model shows large monotonic changes in explosion energy or strong spin-kick alignment already at moderate spins, the generalization fails.","tokens_in":27252,"feed_emoji":"🌌","tokens_out":924,"duration_ms":10946,"temperature":0.7,"pith_summary":"This paper runs a controlled suite of three-dimensional core-collapse simulations of a single 9-solar-mass star, varying only the initial core spin from zero to rapid rates while deliberately omitting magnetic fields. The authors show that explosion energy, shock asymmetry, neutrino heating, residual neutron-star mass, and nucleosynthetic yields all change only modestly across that range; the dependence is non-monotonic and never large. Only the fastest rotator produces clear spin-kick alignment, low-T/|W| spiral-arm modes, and a distinctly stronger gravitational-wave signal. Because collapse amplifies the core period by a factor of roughly four thousand, the modest observed birth periods of radio pulsars imply that most progenitor cores were already spinning slowly. The result matters because it isolates pure hydrodynamic rotation from the more dramatic magnetorotational effects that dominate the literature, and it suggests that for the common class of early-exploding low-mass progenitors rotation can be treated as a secondary correction.","feed_headline":"Rotation barely changes low-mass supernova explosions","feed_subtitle":"Only the fastest spin produces spiral arms, aligned kicks, and stronger gravitational waves","key_machinery":"A controlled sequence of long-term 3D multi-group radiation-hydrodynamics runs of the same 9-solar-mass progenitor, differing only in the Eriguchi-Müller cylindrical rotation profile (Ω₀ = 0, 0.01, 0.1, 1.0 rad s⁻¹), carried to saturation so that asymptotic observables can be compared directly.","core_discovery":"For a low-mass, low-compactness progenitor that explodes early, the effects of pure rotation on explosion energy, blast asymmetries, neutrino heating, nucleosynthetic yields, and residual neutron-star mass remain small and non-monotonic across two orders of magnitude in initial spin; only the most rapid rotator develops T/|W| ~ 0.05 corotation instabilities, spiral arms, spin-kick alignment, and elevated gravitational-wave emission.","pith_inferences":["Magnetized versions of the same rapid rotator would likely convert the modest rotational reservoir into jet-like morphology and higher energy, recovering the classic magnetorotational channel.","If more massive or binary-stripped progenitors retain higher core spins, the spin-kick correlation observed in some pulsars may be explained without invoking post-explosion mechanisms.","The factor-of-4000 spin-up sets a quantitative target for asteroseismic and white-dwarf spin measurements that can be checked against the same angular-momentum-transport physics.","A denser grid of intermediate spins would locate the sharp threshold between random and aligned kicks, testing whether alignment is a continuous or threshold phenomenon."],"forward_implications":["For low-mass early-exploding progenitors, pure rotation can be treated as a small correction to non-rotating models when predicting energy, yields, and residual mass.","Observed radio-pulsar birth periods of hundreds of milliseconds imply typical pre-collapse core periods of minutes rather than seconds.","Clear spin-kick alignment and strong low-T/|W| spiral modes appear only above a high spin threshold, so most ordinary pulsars need not show them.","Gravitational-wave signals from ordinary core-collapse events should lack the cascade of discrete T/|W| bands seen only in the fastest rotator.","Nucleosynthetic differences driven by rotation alone are smaller than those already produced by modest convective seed perturbations."],"fun_headline_variants":["Rotation barely affects low-mass core-collapse supernovae","Spin alone weakly alters low-mass supernova explosion energy","Only fastest spins spark spiral arms in low-mass supernovae","Muted rotation effects in early-exploding low-mass progenitors","Low-mass supernova outcomes change little with pure spin"],"cache_read_input_tokens":16512,"weakest_assumption_plain":"The claim that rotation is muted for most supernova cores rests on a single early-exploding low-mass progenitor and on the deliberate exclusion of magnetic fields.","fun_headline_variants_meta":{"raw":{"variants":["Rotation barely affects low-mass core-collapse supernovae","Spin alone weakly alters low-mass supernova explosion energy","Only fastest spins spark spiral arms in low-mass supernovae","Muted rotation effects in early-exploding low-mass progenitors","Low-mass supernova outcomes change little with pure spin"]},"model":"grok-4.5","effort":"low","cost_usd":0.006042,"raw_usage":{"total_tokens":1627,"prompt_tokens":834,"num_sources_used":0,"completion_tokens":87,"cost_in_usd_ticks":60420000,"prompt_tokens_details":{"text_tokens":834,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":706,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":834,"tokens_out":87,"duration_ms":7260,"temperature":1.0,"reasoning_tokens":706,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-10T23:50:03.769259+00:00","model_set":{"reader":"grok-4.5"},"falsifier":"Repeat the same rotation sequence for a higher-compactness progenitor that explodes later; if that model shows large monotonic changes in explosion energy or strong spin-kick alignment already at moderate spins, the generalization fails.","supporting_citations":[],"review_version":1}