{"id":"238c39c5-90bd-46fc-96df-8db5785916ed","arxiv_id":"2607.07122","paper_version":1,"verdict":"ACCEPT","confidence":"HIGH","novelty_score":6.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":8,"one_line_summary":"Intermediate-redshift galaxies show systematically higher dust attenuation at fixed star formation rate surface density than local galaxies, with the excess strongest for galaxies below the star-forming main sequence.","lead":"This paper finds that the relationship between dust attenuation and star formation rate surface density in galaxies is not universal: intermediate-redshift galaxies show systematically higher dust attenuation than local galaxies at the same star formation rate. This matters because dust corrections are routinely applied to derive star formation rates, and using local calibrations at higher redshift may systematically bias results.","discovery_kind":"unclear","skeptic_critique":{"model":"glm-5.2","headline":"Hβ stellar absorption correction at SNR~3 may systematically inflate Balmer-decrement-based A_V in MAGPI, with the effect strongest for older stellar populations below the SFMS — matching the observed ΔSFMS-dependent offset pattern.","rationale":"The reader correctly identifies that the comparability of BD measurements between surveys is the key assumption, but focuses on surface brightness selection effects, which the paper actually tests (Section 4.6) and finds the offset persists or strengthens. The more precise concern is about flux measurement systematics in Hβ, specifically the stellar absorption correction at low SNR. The paper's robustness tests are thorough for selection effects but do not address measurement systematics. The ΔSFMS dependence of the offset is the strongest argument both for and against this concern: it matches the expected signature of stellar absorption residuals (stronger for older populations below SFMS), but the intra-MAGPI ΔSFMS slope variation provides partial evidence for a physical component. The paper's claims are appropriately measured ('may not fully describe,' 'not universal'), and the multiple consistency checks (matched comparison, internal redshift test, alternative SFMS) provide genuine support. The concern identifies an untested but plausible systematic that could partially inflate the offset, particularly below the SFMS. However, even if a fraction of the offset is systematic, the qualitative finding — that locally calibrated relations show tension at intermediate redshift — likely stands. The verdict should remain ACCEPT: the paper presents a well-constructed empirical analysis with appropriate caveats, and the concern identifies a worthwhile follow-up test rather than a fundamental flaw.","tokens_in":26098,"tokens_out":6061,"duration_ms":363873,"concrete_test":"Inject artificial emission lines with known intrinsic BD = 2.86 into both MAGPI and MaNGA continuum spectra (with realistic noise at SNR~3 for Hβ), spanning a range of stellar population ages/D4000 values. Recover BD using the standard PPXF/GANDALF pipeline. If the recovered BD is systematically higher for MAGPI-like spectra (especially for older populations), and the bias correlates with D4000 or stellar age in a way that produces a ΔSFMS-dependent offset matching the observed 0.40/0.28/0.07 mag pattern, then a significant fraction of the offset is measurement systematic rather than physical.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim requires that the ~0.35 mag A_V offset between MAGPI and MaNGA is physical, not instrumental. The paper thoroughly tests selection effects (detection limits, PSF matching, environment) but does not directly test for systematic differences in Hβ flux measurement between surveys. This matters because: (1) A 0.35 mag A_V offset corresponds to only a ~6% difference in the Balmer decrement (BD ≈ 3.03 vs 2.86), well within the range of stellar absorption correction residuals at SNR~3. (2) The ΔSFMS dependence of the offset (0.40 mag below SFMS, 0.07 mag above) is exactly the pattern expected if stellar absorption corrections are less accurate for older stellar populations (below SFMS) at lower SNR: older populations have stronger Hβ absorption, making the correction harder and residual under-correction inflating BD. (3) While PPXF/GANDALF models the stellar continuum for both surveys, the accuracy of the Hβ absorption correction depends on SNR and spectral quality, which differ systematically between MUSE at z~0.3 (SNR~3 for Hβ) and MaNGA at z<0.1 (intrinsically higher quality spectra even when cut to SNR>3). The paper's robustness tests address whether different spaxels are selected, not whether the same spaxels would yield the same BD in both surveys. The intra-MAGPI ΔSFMS slope variation (Table 1) is a separate physical trend that doesn't rule out an additive normalization systematic in the cross-survey comparison. This concern does not overturn the finding — the multiple consistency checks and the internal redshift test (Fig. 7) provide supporting evidence — but it identifies the most important untested systematic, one whose expected signature matches the observed ΔSFMS dependence.","agreement_with_reader":"partial"},"referee_report":{"model":"glm-5.2","summary":"This paper uses spatially resolved Balmer-decrement measurements from the MAGPI survey (178 galaxies at 0.25 < z < 0.42) to test whether the locally calibrated resolved A_V–Sigma_SFR relation from MaNGA (Paper I) remains valid at intermediate redshift. The authors find that MAGPI spaxels exhibit systematically higher A_V at fixed Sigma_SFR than MaNGA, with an overall median offset of ~0.35 mag. After matching galaxies in stellar mass and Delta_SFMS via Monte Carlo realizations, the offset persists: strongest below the SFMS (Delta A_V ~ 0.40 mag), weaker on the SFMS (~0.28 mag), and minimal above the SFMS (~0.07 mag). Robustness tests for detection limits, PSF matching, environmental selection, and alternative SFMS parameterization are presented. The authors conclude that the resolved A_V–Sigma_SFR relation is not universal and that locally calibrated attenuation prescriptions may not adequately describe intermediate-redshift galaxies, particularly those below the SFMS.","tokens_in":26619,"tokens_out":1692,"duration_ms":236797,"significance":"The question of whether locally calibrated dust attenuation relations remain valid at higher redshift is important for spatially resolved studies of galaxy evolution, as systematic biases in A_V propagate directly into derived Sigma_SFR and other physical quantities. The paper's strength lies in its careful matched comparison framework: Monte Carlo matching in M* and Delta_SFMS isolates the redshift/population effect from simple population mixing, and the suite of robustness tests (detection limits, PSF matching, environment, alternative SFMS) is thorough and well-designed. The finding that the offset depends on Delta_SFMS — strongest for galaxies below the SFMS — is a novel and physically interesting result that connects resolved dust properties to global evolutionary state. The intra-MAGPI redsplit consistency check (Section 5, Fig. 7), while limited in dynamic range, adds internal corroboration. The paper is suitable for the journal's scope and will be of interest to the extragalactic IFS community.","major_comments":[{"comment":"The most important unaddressed systematic is the potential for differential Hβ stellar absorption correction residuals between MAGPI and MaNGA. The authors note (Section 3.1) that PPXF/GANDALF models the stellar continuum before measuring emission-line fluxes for both surveys, and Battisti et al. (2026) is cited for MAGPI-specific details. However, the paper does not directly test whether the Hβ absorption correction performs equivalently at the different SNR regimes and spectral resolutions of MUSE (z~0.3, SNR>3 for Hβ) versus MaNGA (z<0.1, reconstructed to SNR>3 but intrinsically higher quality). This matters because: (1) a 0.35 mag A_V offset corresponds to only a ~6% difference in the Balmer decrement (BD ~ 3.03 vs 2.86), which is within the plausible range of stellar absorption correction residuals at SNR~3; (2) the Delta_SFMS dependence of the offset (0.40 mag below, 0.07 mag above","section":null},{"comment":"the SFMS) is exactly the pattern expected if Hβ absorption corrections are less accurate for older stellar populations (which dominate below the SFMS) at lower SNR — older populations have stronger Hβ absorption features, making the correction harder and residual under-correction inflating BD. The detection-limit test (Section 4.6) addresses whether different spaxels are selected but not whether the same spaxels would yield the same BD in both surveys. I recommend the authors add a direct test or quantitative discussion of this systematic. Possible approaches include: (a) injecting mock emission lines into both MAGPI- and MaNGA-like spectra with known BD and recovering A_V to quantify any survey-dependent bias; (b) comparing the distribution of Hβ equivalent widths or absorption corrections between matched MAGPI and MaNGA samples; or (c) at minimum, a quantitative discussion of why the p","section":null},{"comment":"PPXF/GANDALF correction is expected to be equivalent across surveys despite different SNR and spectral resolution, with reference to any existing validation of this pipeline at low SNR. This is load-bearing for the central claim because if even ~0.1–0.15 mag of the offset below the SFMS is attributable to absorption correction residuals, the physical interpretation is materially affected.","section":null}],"minor_comments":[{"comment":"Section 3.1: The SNR>3 threshold for MAGPI is lower than the SNR>5 used in Paper I for MaNGA. The authors reconstruct MaNGA maps at SNR>3 for consistency, which is appropriate. However, it would be useful to briefly quantify how many spaxels/galaxies are added or lost in MaNGA when moving from SNR>5 to SNR>3, and whether the MaNGA A_V–Sigma_SFR relation changes when this threshold is shifted.","section":null},{"comment":"Section 4.1: The Delta_SFMS bin boundaries (-0.3, +0.3) are adopted without explicit justification. A brief comment on the sensitivity of the results to these boundaries would strengthen the analysis, particularly given that the 'above SFMS' bin contains only 15% of MAGPI galaxies.","section":null},{"comment":"Figure 2: The y-axis range is not specified in the caption. For the reader's benefit, it would help to state the A_V range shown and ensure the MaNGA error bars (red squares) are visible — they appear small in the figure.","section":null},{"comment":"Table 1: The intercept 'b' values (4.02, 2.88, 2.18) are large because the fit is in log10(Sigma_SFR) units. A footnote or caption note clarifying the units of the fit (log10(Sigma_SFR / Msun yr^-1 kpc^-2)) would help readers interpret these values.","section":null},{"comment":"Section 4.4: The matching tolerance of ±0.1 dex in both log M* and Delta_SFMS is reasonable, but the fraction of MAGPI galaxies that find a MaNGA match within this tolerance is not stated. Please report the match success rate.","section":null},{"comment":"Section 5, Fig. 7: The intra-MAGPI redshift split test is a nice consistency check, but the sample sizes in each redshift bin are not given. Please state N_galaxies in each bin and note the caveat about limited statistical power more explicitly.","section":null},{"comment":"The paper uses both 'A_V' and 'AV' (without subscript) in different places (e.g., abstract vs. equations). Standardizing notation throughout would improve readability.","section":null},{"comment":"Reference list: Battisti et al. (2026) is cited for MAGPI emission-line products but appears to be 'submitted' — please update with final reference details if available by the time of revision.","section":null}],"recommendation":"minor_revision","confidential_remarks":"The skeptic's concern about Hβ stellar absorption correction residuals is the most substantive unaddressed systematic and should be the primary focus of the revision. The paper's existing robustness tests are genuinely thorough, but they all operate at the level of spaxel selection rather than flux measurement fidelity. The authors are well-positioned to address this — they have the data and pipeline expertise to run a direct test. If they can show that the absorption correction is equivalent (or quantitatively bound the residual), the paper's central claim is on solid ground. The intra-MAGPI Delta_SFMS slope variation (Table 1) is a physically real trend that does not depend on the cross-survey comparison and should be emphasized as an independent result."},"author_rebuttal":null,"desk_editor":{"model":"glm-5.2","letter":"The main thing to know: this paper shows that the resolved A_V–Σ_SFR relation from MaNGA does not hold at z~0.3. MAGPI galaxies are more attenuated at fixed Σ_SFR, and the offset depends on ΔSFMS — strongest below the SFMS (~0.40 mag), minimal above (~0.07 mag). That's a useful, practical result for anyone applying locally calibrated attenuation corrections at intermediate redshifts. The matched analysis in M* and ΔSFMS is well done, and the battery of robustness tests (detection limits, PSF matching, environmental selection, alternative SFMS) is thorough and honest about what each does and doesn't fix. The internal redshift test within MAGPI (Fig. 7) is a nice consistency check, even if the baseline is short. Credit is due for the systematic approach — they clearly tried to kill their own result and couldn't. The ΔSFMS-dependent slope variation (Table 1) is a genuine physical trend within MAGPI that doesn't depend on the cross-survey comparison. The stress-test concern about Hβ stellar absorption is the one soft spot worth taking seriously. A 0.35 mag A_V offset is only a ~6% difference in the Balmer decrement, which is within the range where residual stellar absorption corrections could matter — especially at SNR~3 for Hβ in MAGPI versus higher-quality MaNGA spectra. The ΔSFMS dependence of the offset is exactly the pattern you'd expect if older stellar populations (below the SFMS) have stronger Hβ absorption that's harder to correct at lower SNR. The paper tests whether different spaxels are selected between surveys, but not whether the same spaxel would yield the same Balmer decrement in both. That said, this concern doesn't overturn the result. The intra-MAGPI trend, the detection-limit test (which slightly increases the offset), and the PSF matching all point to a real effect. The stellar absorption issue is the most important untested systematic, and its expected signature matches the observed pattern — but it's additive, not load-bearing. The sample is modest (178 galaxies, 8224 spaxels) and the redshift baseline is small, which the authors acknowledge. This is a paper for people working in resolved galaxy studies, IFU survey analysis, and SFR calibration. It deserves a serious referee who should push hard on the Hβ absorption question — ideally asking for a direct test of whether the stellar continuum fitting gives consistent Balmer decrements on shared or simulated spectra at the two surveys' typical SNR. If that checks out, the central claim is solid.","headline":"Solid empirical result: resolved A_V–Σ_SFR relation is not universal, with a specific untested systematic worth flagging","tokens_in":27276,"tokens_out":635,"would_cite":true,"duration_ms":120669,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"glm-5.2","headline":"Dust–star formation relation breaks down beyond local universe","keywords":["dust attenuation","star formation rate surface density","Balmer decrement","resolved galaxy properties","star-forming main sequence","intermediate redshift","MAGPI survey","MaNGA survey"],"falsifier":"If the A_V–Σ_SFR relation at intermediate redshift were shown to match the local relation when a more complete or unbiased sample of HII regions is observed — for instance, with deeper spectroscopy recovering the faint Hβ emission from less-obscured regions that the current SNR>3 threshold misses — the observed offset would shrink or vanish, undermining the non-universality claim.","tokens_in":26185,"feed_emoji":"🔭","tokens_out":2055,"duration_ms":71464,"temperature":0.7,"pith_summary":"The paper claims that the spatially resolved relationship between dust attenuation and star formation rate surface density — a relation calibrated in the local universe and widely used to correct galaxy measurements — is not universal. By comparing 178 galaxies at intermediate redshift (z~0.3) from the MAGPI survey with local galaxies from MaNGA, the authors find that distant galaxies show systematically more dust obscuration at a given star formation rate density, even after matching galaxies in stellar mass and position relative to the star-forming main sequence. The excess attenuation is strongest in galaxies below the main sequence (those transitioning toward quiescence) and nearly absent in galaxies above it. This means dust attenuation on kiloparsec scales depends not just on local star formation but on the global evolutionary state of the host galaxy, and that applying local calibrations to intermediate-redshift galaxies introduces systematic biases in inferred star formation rates.","feed_headline":"Dust–star formation relation breaks down beyond local universe","feed_subtitle":"Galaxies at z~0.3 show up to 0.4 mag excess dust attenuation at fixed star formation rate, breaking locally calibrated corrections used to测量","key_machinery":"The Balmer decrement — the observed ratio of the Hα to Hβ hydrogen emission lines — serves as the primary diagnostic. Under Case B recombination, the intrinsic ratio is fixed at 2.86; deviations from this value measure dust reddening along the line of sight to ionised gas in star-forming regions. The paper constructs spatially resolved attenuation maps from this ratio for 178 galaxies, then compares the resulting A_V–Σ_SFR relation against the local benchmark from MaNGA, using Monte Carlo matching in stellar mass and offset from the star-forming main sequence to isolate the intrinsic difference.","core_discovery":"The resolved A_V–Σ_SFR relation is not universal across redshift. At fixed star formation rate surface density, galaxies at z~0.3 are more dust-attenuated than local galaxies by ~0.28 mag on average, with the excess reaching ~0.40 mag in galaxies below the star-forming main sequence and dropping to ~0.07 mag above it. The dependence on global star-forming state implies that nebular attenuation is jointly regulated by local star formation activity and the host galaxy's evolutionary state, with the decoupling more pronounced at intermediate redshift.","pith_inferences":[],"forward_implications":[],"fun_headline_variants":["Local dust attenuation calibrations fail at intermediate redshift","Dust–star formation link shifts with redshift and galaxy evolution","Galaxies at z~0.3 show excess dust attenuation not seen locally","Resolved dust attenuation depends on host galaxy evolution, not just local star formation","MAGPI survey challenges universality of resolved dust attenuation relations"],"cache_read_input_tokens":0,"weakest_assumption_plain":"The Balmer decrement is assumed to trace the same physical dust geometry at z~0.3 as in the local universe. If intermediate-redshift observations preferentially sample more embedded or dustier star-forming regions due to surface brightness selection effects not fully captured by the paper's luminosity threshold tests, part of the observed excess could be observational rather than physical.","fun_headline_variants_meta":{"raw":{"variants":["Local dust attenuation calibrations fail at intermediate redshift","Dust–star formation link shifts with redshift and galaxy evolution","Galaxies at z~0.3 show excess dust attenuation not seen locally","Resolved dust attenuation depends on host galaxy evolution, not just local star formation","MAGPI survey challenges universality of resolved dust attenuation relations"]},"model":"glm-5.2","effort":"low","cost_usd":0.0,"raw_usage":{"total_tokens":807,"prompt_tokens":717,"completion_tokens":90,"prompt_tokens_details":null},"tokens_in":717,"tokens_out":90,"duration_ms":22831,"temperature":1.0,"reasoning_tokens":null,"cache_read_input_tokens":0,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-09T19:35:33.551571+00:00","model_set":{"reader":"glm-5.2"},"falsifier":"If the A_V–Σ_SFR relation at intermediate redshift were shown to match the local relation when a more complete or unbiased sample of HII regions is observed — for instance, with deeper spectroscopy recovering the faint Hβ emission from less-obscured regions that the current SNR>3 threshold misses — the observed offset would shrink or vanish, undermining the non-universality claim.","supporting_citations":[],"review_version":1}