{"id":"f7b05f88-8f58-493f-b8de-bb615c62796e","arxiv_id":"2508.06654","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":4.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":2,"one_line_summary":"SN 2023ixf produced 0.046 ± 0.007 solar masses of nickel and ejected less than 9 solar masses, based on bolometric light curve modeling.","lead":"Astronomers measured the nickel mass and ejecta mass of the nearby supernova SN 2023ixf by tracking its brightness for 400 days. The supernova produced about 0.046 solar masses of radioactive nickel and ejected less than 9 solar masses of material, a relatively low mass for this type of explosion.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Gamma-ray leakage at 400 d may bias M_Ni and M_ej; the paper's own low ejecta mass makes full trapping unlikely.","rationale":"The reader's verdict is UNVERDICTED because the supplied text is heavily corrupted, and I agree that the paper cannot be fully audited from the provided material. The most consequential scientific concern is not the unreadability itself but the physical consistency of the method with the claimed result: a low-M_ej object at 400 days is exactly the regime where gamma-ray escape matters. Thus both the quoted M_Ni and the M_ej comparison with SN 2017eaw are hostage to the deposition treatment. The proposed check isolates this by refitting the same tail data with and without a time-dependent deposition function. If the result is unchanged, the concern is retired; if not, the difference must be propagated to the comparison with SN 2017eaw. I keep the reader's UNVERDICTED verdict, hence UNCHANGED; a clean check could move the paper toward CONDITIONAL or ACCEPT, but that is not established here.","tokens_in":12756,"tokens_out":12563,"duration_ms":160204,"concrete_test":"Take the paper's late-time bolometric points (t > 200 d) and refit L(t) = M_Ni * eps_Co * exp(-t/111.3 d) * D(t), with D(t) = 1 - exp[-(t0/t)^2] where t0 is computed from the adopted (M_ej, E). Compare D(400 d) and the resulting M_Ni with the published 0.046 +/- 0.007. If D(400 d) < 0.7 or M_Ni shifts by more than the quoted 0.007 M_sun relative to the full-trapping fit, the headline mass inferences are not robust; if the paper already used such a deposition function, the check will quantify its actual effect.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The load-bearing unverified assumption is that the 400-day radioactive tail is fully powered by 56Co decay with complete gamma-ray trapping. The same abstract reports M_ej <= 9 M_sun; with E ~ 1e51 erg this gives expansion velocities ~3000 km/s and R ~ 1e16 cm at 400 d, so the gamma-ray optical depth is tau_gamma ~ kappa_gamma M_ej / (4 pi v^2 t^2) ~ 0.3-1.0 for kappa_gamma ~ 0.03 cm^2/g. Escape is therefore non-negligible. If the tail fit sets the deposition fraction to unity, M_Ni would be underestimated by roughly a factor of 1.5-3x; the value 0.046 +/- 0.007 would move well outside its quoted uncertainty, and the corrected nickel mass can feed back into the ejecta-mass comparison with SN 2017eaw. The provided full text is corrupted, so I cannot confirm whether a time-dependent gamma-ray deposition function was included. The central claim is only sound if the model demonstrably includes such deposition and propagates the associated systematic uncertainty.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper reports new RC80/BRC80 photometry of SN 2023ixf and constructs a bolometric light curve extending to roughly 400 days after explosion. From the late-phase radioactive tail it derives M_Ni = 0.046 ± 0.007 M_sun, and from comparisons with hydrodynamic and semi-analytic radiative-diffusion models it derives M_ej ≲ 9 M_sun, in contrast to SN 2017eaw (M_ej ≳ 15 M_sun). The abstract is the only fully readable portion of the submitted text; the body is severely corrupted (mojibake), so the photometric data, bolometric corrections, model fits, and uncertainty propagation cannot be independently checked.","tokens_in":13067,"tokens_out":5320,"duration_ms":64417,"significance":"If the quoted values survive scrutiny, the paper would be a useful contribution to the Type II SN sample: it would indicate a relatively low ejecta mass for a well-observed nearby SN II and sharpen the comparison with SN 2017eaw. The use of two independent model families is a strength, and the tail-based nickel-mass estimate with a stated uncertainty is a testable claim. However, the unreadable manuscript body and the unaddressed gamma-ray-deposition question prevent the significance from being assessed at this stage.","major_comments":[{"comment":"The submitted text is corrupted from the first line after the abstract; equations, tables, figure captions, and most prose are unreadable. I cannot verify the distance/reddening assumptions, the bolometric correction, the construction of the late-time tail, the model grids, or the quoted uncertainties. This is a load-bearing problem, not a presentation issue: the central claims rest on these details. A readable manuscript is a prerequisite for review.","section":"Full text (after Abstract)"},{"comment":"The abstract states that M_Ni is inferred from the bolometric light curve up to 400 d and independently gives M_ej ≲ 9 M_sun. With a canonical explosion energy ~1e51 erg, M_ej ~ 9 M_sun, and t ~ 400 d, the expansion velocity is ~3000 km/s and the radius ~1e16 cm; for a gamma-ray opacity ~0.03 cm^2/g, the gamma-ray optical depth is τ_γ ~ 0.3–1.0. Full trapping is therefore not a safe assumption. If the tail fit assumes full trapping, M_Ni would be underestimated by roughly a factor 1.5–3, far outside the stated ±0.007. The paper must demonstrate the time-dependent gamma-ray deposition treatment used in the tail analysis and in both model families, and must propagate the resulting systematic uncertainty into M_Ni and M_ej.","section":"Abstract; late-phase bolometric light curve"},{"comment":"The inferred M_Ni feeds directly into the comparison with SN 2017eaw: if gamma-ray leakage is ignored, the low M_Ni may bias the derived M_ej downward. The abstract gives no indication of how the two model families treat deposition differently. To support the claim 'M_ej ≲ 9 M_sun contrary to SN 2017eaw', the paper should provide a consistency check—e.g., re-fit the tail with a deposition function and show how M_Ni and M_ej change—or otherwise quantify the sensitivity to the deposition assumption.","section":"Abstract; SN 2017eaw comparison"}],"minor_comments":[{"comment":"The abstract should state the adopted distance to M101 and the line-of-sight reddening, since M_Ni scales directly with distance and the bolometric correction depends on reddening. If these are given in the body, they must be legible after re-encoding.","section":"Abstract"},{"comment":"The inequality M_ej ≲ 9 M_sun is not a measured value; the text should report the best-fit value and a confidence interval or model range once the manuscript is readable.","section":"Abstract"},{"comment":"Several blocks resembling tables and figure captions are only partially legible in the current encoding. After fixing the encoding, all captions, column headers, and table values should be checked for integrity.","section":"General"}],"recommendation":"uncertain","confidential_remarks":"The received PDF is not reviewable: the entire body is a character-encoding artifact. I would ask the authors to resubmit a readable PDF before substantive review. Once readable, the gamma-ray deposition treatment is the first item to check; if the tail fit does not include a time-dependent deposition function, the central M_Ni value is likely biased and the M_ej comparison with SN 2017eaw would need revision. This is an editorial gate, not a scientific verdict."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"The thing to know: this paper reports new RC80/BRC80 photometry of SN 2023ixf out to 400 days and derives M_Ni = 0.046 ± 0.007 Msun and M_ej ≤ 9 Msun, a clear contrast to SN 2017eaw. That would be a useful data point. But I can't verify any of it from what I was given: the full text is mojibake, only the abstract and some figure fragments are legible.\n\nWhat is genuinely new: the new photometry itself, and the extended 400-day bolometric light curve. The abstract says they compared with both hydrodynamical simulations and semi-analytic diffusion codes, which is the right way to do this. The nickel mass is a standard late-time estimate, and the M_ej constraint is the kind of thing that feeds progenitor-mass discussions.\n\nThe soft spots are real. First, the gamma-ray leakage concern raised in the stress test is legitimate. With M_ej ≤ 9 Msun and a typical explosion energy, the ejecta becomes optically thin to gamma-rays well before 400 days. If the authors fit the tail assuming full trapping, M_Ni would be underestimated, possibly by 1.5–3x, and the quoted uncertainty (0.007) doesn't cover that systematic. I can't tell from the abstract whether they included a time-dependent deposition function. Second, the distance to M101 and the reddening are load-bearing; any error moves both M_Ni and M_ej. Third, the comparison with SN 2017eaw may be sensitive to how the two events' bolometric corrections are handled, but that's a secondary point.\n\nSo: the central claim might hold, but it's not yet demonstrated in front of me. This deserves a serious referee who can read the full text and check the deposition treatment. I'd send it to peer review, with a request that the authors explicitly justify or relax the full-trapping assumption and report the systematic uncertainty. I wouldn't cite it myself until that's in the record. The reading group might find the 2017eaw contrast interesting, but I'd wait for a clean version.","headline":"Potentially interesting low-ejecta result for SN 2023ixf, but the supplied text is unreadable and the gamma-ray trapping assumption needs checking.","tokens_in":13621,"tokens_out":2701,"would_cite":false,"duration_ms":27505,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"SN 2023ixf's late bolometric light curve yields 0.046 solar masses of radioactive nickel and an ejecta of no more than 9 solar masses.","keywords":["SN 2023ixf","core-collapse supernova","bolometric light curve","nickel-56 mass","ejecta mass","M101","Type II supernova","radioactive decay curve"],"falsifier":"Look for a bolometric decay slope after roughly day 100 that is steeper than the 77.2-day half-life of cobalt-56 would produce, or for an infrared excess or flattening at late times; either would show an additional power source or gamma-ray leakage, breaking the radioactive-trapping assumption. Alternatively, an independent geometric distance to M101 that shifts the luminosity beyond the quoted uncertainties would rescale $M_{\\rm Ni}$ (which scales with distance squared) and could push the ejecta mass above $9\\,M_\\odot$.","tokens_in":12745,"feed_emoji":"💥","tokens_out":8929,"duration_ms":90535,"temperature":0.7,"pith_summary":"This paper follows SN 2023ixf, a core-collapse supernova in the galaxy M101 — the explosion of a massive star — for roughly 400 days, and builds its bolometric light curve, the total luminosity across all wavelengths over time, from multi-band photometry. It argues that the late-time tail of that curve is powered by the radioactive decay of nickel-56 and cobalt-56, and from the tail's luminosity it derives an initial nickel mass of $M_{\\rm Ni}=0.046\\pm0.007\\,M_\\odot$. Matching the whole light curve to both hydrodynamical explosion models and semi-analytic radiative-diffusion models, the paper concludes that the ejecta mass, the mass of material thrown off in the explosion, is at most about $9\\,M_\\odot$, notably lower than the $15\\,M_\\odot$ or more inferred for the similar hydrogen-rich supernova SN 2017eaw. If this is right, SN 2023ixf is a low-yield core-collapse event, either from a less massive progenitor or from a star that lost much of its envelope before exploding.","feed_headline":"SN 2023ixf's nickel mass pinned at 0.046 suns","feed_subtitle":"A 400-day bolometric light curve shows the supernova's ejecta is under 9 solar masses, well below SN 2017eaw.","key_machinery":"The paper's working object is the bolometric light curve — the total luminosity radiated at all wavelengths as a function of time — assembled from multi-band photometry and extended to roughly 400 days after explosion. The argument's engine is the radioactive-decay tail: after the first few months, the luminosity is set by the energy released as nickel-56 decays to cobalt-56 and then to iron-56, so the tail's absolute level fixes the initial nickel mass, while the rise, peak, and decline of the full curve are matched against hydrodynamical explosion models and semi-analytic radiative-diffusion models (simplified descriptions of radiation leaking out of the expanding ejecta) to fix the ejecta","core_discovery":"The central claim is that SN 2023ixf's bolometric light curve, observed to 400 days after explosion, is well described by a standard radioactive-decay-powered supernova with a small nickel mass and a small ejecta mass. The paper infers $M_{\\rm Ni}=0.046\\pm0.007\\,M_\\odot$ from the late-phase tail and $M_{\\rm ej}\\lesssim9\\,M_\\odot$ from comparing the full curve to two independent classes of models, hydrodynamical simulations and semi-analytic radiative-diffusion codes. It contrasts this with SN 2017eaw, whose ejecta mass is estimated at $\\gtrsim15\\,M_\\odot$, and takes the difference as evidence that the two superficially similar hydrogen-rich explosions came from different progenitor configura","pith_inferences":["Editorial inference: the complete-trapping assumption is load-bearing; if gamma rays escape, the reported $M_{\\rm Ni}$ is a lower limit, so the gap with SN 2017eaw could shrink.","Editorial inference: a low ejecta mass could also result from a high-mass progenitor that shed most of its hydrogen envelope before exploding; distinguishing that from a genuinely low-mass progenitor requires measuring the surviving hydrogen mass, for example through H-alpha line strength at nebular phases.","Editorial inference: applying the same 400-day bolometric fitting to a sample of nearby Type II supernovae would test whether low nickel mass and low ejecta mass correlate with early circumstellar interaction, which would point to mass loss as the controlling variable."],"forward_implications":["If confirmed, SN 2023ixf joins a low-nickel, low-ejecta class of Type II supernovae, so nucleosynthesis yields and explosion energies for such events would need to be revised downward.","The ejecta-mass gap between SN 2023ixf and SN 2017eaw implies hydrogen-rich supernovae do not form one progenitor family; progenitor mass and pre-explosion mass loss must vary event by event.","A 400-day photometric baseline from modest robotic telescopes is enough to constrain nickel mass, making similar late-time monitoring feasible for other nearby supernovae.","The derived parameters give late-time spectroscopy a concrete target: measured line profiles should match a low-mass, low-nickel ejecta if the model is correct."],"supporting_citations":[],"fun_headline_variants":["SN 2023ixf's ejecta under 9 suns, unlike SN 2017eaw","400-day light curve exposes SN 2023ixf's light ejecta","SN 2023ixf: nickel mass 0.046 suns, ejecta below 9","SN 2023ixf's small nickel and ejecta from 400-day curve"],"cache_read_input_tokens":2816,"weakest_assumption_plain":"The mass and nickel estimates assume the entire late-time light curve is powered by fully trapped radioactive decay of nickel-56 and cobalt-56, with known distance and dust extinction; if gamma rays leak, another power source contributes, or the distance is off, both masses change.","fun_headline_variants_meta":{"raw":{"variants":["SN 2023ixf's ejecta under 9 suns, unlike SN 2017eaw","400-day light curve exposes SN 2023ixf's light ejecta","SN 2023ixf: nickel mass 0.046 suns, ejecta below 9","SN 2023ixf's small nickel and ejecta from 400-day curve"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000884,"raw_usage":{"total_tokens":3641,"prompt_tokens":715,"completion_tokens":2926,"prompt_tokens_details":{"cached_tokens":256},"prompt_cache_hit_tokens":256,"prompt_cache_miss_tokens":459,"completion_tokens_details":{"reasoning_tokens":2840}},"tokens_in":459,"tokens_out":2926,"duration_ms":19905,"temperature":1.0,"reasoning_tokens":2840,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-05T22:37:01.547292+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Look for a bolometric decay slope after roughly day 100 that is steeper than the 77.2-day half-life of cobalt-56 would produce, or for an infrared excess or flattening at late times; either would show an additional power source or gamma-ray leakage, breaking the radioactive-trapping assumption. Alternatively, an independent geometric distance to M101 that shifts the luminosity beyond the quoted uncertainties would rescale $M_{\\rm Ni}$ (which scales with distance squared) and could push the ejecta mass above $9\\,M_\\odot$.","supporting_citations":[],"review_version":1}