{"id":"98e3a189-c745-422f-a6f7-8496bc58a768","arxiv_id":"2601.08112","paper_version":3,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"At z≈0, stars, dust, neutral gas, and black holes in galaxies contain only ≈5% of cosmic baryons, with dust- and gas-mass histories derived from ~800,000 GAMA/DEVILS galaxies.","lead":"Using infrared and optical light from 800,000 galaxies, this paper counts how much of the universe's ordinary matter is locked up in stars, dust, neutral gas, and black holes out to redshift 3. It finds these galaxy-bound components make up only about 5% of all baryons, with the rest ionized and spread through intergalactic space.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Global dust-mass calibration and α-prior dependence leave the CDMH/CGMH scale and high-z shape uncertain, though the 5% baryon fraction is robust.","rationale":"The reader's weakest assumption correctly identifies the dust-mass calibration as the central vulnerability. The paper's own text flags the q sensitivity and the α-prior issue explicitly, making this the most credible source of systematic error. The 218-galaxy MAGPHYS comparison is only a low-redshift, FIR-bright anchor; extrapolating it to the full sample, and especially to the ~99% of z>2 DEVILS galaxies without FIR detections, introduces an unquantified scale uncertainty into the CDMH and CGMH. A per-galaxy application of the variable-DTH correction is a feasible and direct test of whether the global shift is sufficient. If the correction changes the high-redshift dust densities significantly, the paper's claims about the CDMH shape and the neutral-gas deficit would need revision. However, the headline 5% baryon fraction is robust because stars dominate the galaxy-bound baryon budget; dust and neutral gas together contribute well under 1 percentage point. Thus the correct verdict remains CONDITIONAL, matching the reader's assessment. I considered whether the LSS correction applied uniformly to stars, dust, and gas might be a load-bearing issue, but that correction is derived from the same galaxy sample and is unlikely to change the main conclusions. I also considered the stellar mass scale (IMF/SPS) as a threat to the 5% figure, but the paper's validation against Driver+22 at z=0 and the fact that even a 0.2 dex shift would keep the census within '≈5 per cent' make this less critical. The dust calibration is the single most load-bearing concern because it directly undermines the two results the reader flagged as central beyond the 5% figure.","tokens_in":24830,"tokens_out":8022,"duration_ms":81191,"concrete_test":"Recompute the dust masses for the full GAMA+DEVILS sample by applying the variable-DTH correction per galaxy using each galaxy's fitted α and the wavelength-dependent DTH(λ) weighting of Eq. 4, instead of shifting all dust masses by a global ≈2.5 factor. Then recompute the CDMH and CGMH as in §5 and §6. If the z>1 points move by more than the quoted 1σ uncertainties in Table A5, or if the peak/decline changes, the global calibration is inadequate and the CDMH-shape claim should be downgraded. As a supplementary check, compare ProSpect versus MAGPHYS dust masses for any DEVILS galaxies at z>1 with FIR detections to test whether the ≈2.5 offset persists at high redshift.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The absolute scale of the cosmic dust and neutral gas histories, and hence the quantitative CDMH shape and the 0.6 dex CGMH deficit versus 21cm measurements, rests on a single calibration step in §3.2: ProSpect dust masses are down-scaled by a global factor ≈2.5, chosen by setting q=0.14 in a variable DTH weighting so that dust masses of 218 bright, low-redshift, FIR-detected GAMA galaxies match MAGPHYS. The paper itself states 'this scaling is sensitive to the value of q. For example, q=0.1 results in ≈3.1 times lower dust masses.' This calibration sample is small, local, and FIR-bright, yet the factor is applied uniformly to all ~800,000 galaxies, including DEVILS galaxies at z>2 where ~99% lack FIR detections (Fig. 1). For those galaxies, the dust mass is controlled by a Gaussian prior on α with mean 2 (σ=1); §3.1 and Fig. 2 show that including FIR data shifts dust masses by ≈0.7 dex because the fit prefers α≈3. The high-redshift CDMH points are therefore prior-dominated, and the global scaling may not hold at high z if the α distribution or the PAH/VSG mass fraction q evolves. Since the CGMH is dust mass divided by a metallicity-dependent DTG, the neutral-gas history inherits the same scale. The 5% baryon fraction itself is dominated by stars and is insensitive to this (dust contributes <0.1%, neutral gas <0.5%), but the paper's two other headline results—the CDMH shape and the HI comparison—are directly affected.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper uses ProSpect SED fits of approximately 800,000 galaxies from GAMA and DEVILS at 02 where almost none have FIR detections. The paper itself notes that q=0.1 gives ~3.1 times lower dust masses, and §3.3 shows that plausible changes in the opacity coefficient can change dust masses by factors of a few. These are systematic uncertainties, but Table A5 quotes CDMH and CGMH uncertainties of only ~0.05 dex and appears not to include them. Because the CGMH is just the dust mass divided by a metallicity-dependent DTG, the reported 0.6 dex offset from 21cm measurements could absorb a rescaling of this order. I ask for a per-object or at least redshift-dependent correction, and for a propagated systematic error envelope in Table A5 and Fig. 9 covering the plausible range","section":"§3.2, Eq. (4); Table A5"},{"comment":"For z>2, Fig. 1 shows that only about 1 per cent of DEVILS sources have MIR/FIR photometry. Their dust masses are therefore controlled by the Gaussian prior on alpha with mean 2 and sigma 1, rather than by direct FIR constraints. Fig. 2 demonstrates that including FIR data shifts the dust-mass posterior by about 0.7 dex because the fit prefers alpha≈3. The high-redshift CDMH points in Fig. 9 and Table A5 (e.g. z=2.311 and 3.090) and the location of the peak at z≈1–2 are thus prior-dominated to a significant degree. Please quantify this sensitivity by rerunning the high-redshift CDMH with an alpha prior centred at 3, or with no prior, and reporting the resulting shape; if this is not possible, the claims about the peak and the high-z decline should be softened.","section":"§3.1, Fig. 2; Fig. 9, Table A5"},{"comment":"The term 'self-consistent' overstates the case for the dust and SMBH components. The dust scale is calibrated to make ProSpect agree with MAGPHYS on 218 galaxies, so the subsequent agreement of the CDMH with MAGPHYS-based literature values is partly by construction. The SMBH mass density is not derived in this paper but is imported from D'Silva et al. (2023, 2025). The 5 per cent baryon census remains a useful aggregation, but the text should describe it as homogeneous in data and fitting infrastructure, while acknowledging that the dust absolute scale is inherited from a MAGPHYS-based calibration and that the SMBH curve is taken from the authors' earlier analysis.","section":"§6, Fig. 12; references to D'Silva et al. (2023, 2025)"}],"minor_comments":[{"comment":"The abstract states the neutral gas deficit is on average ≈0.7 dex lower than 21cm measurements, while the full text and Section 6 say ≈0.6 dex. Please make these consistent.","section":"Abstract vs. §6"},{"comment":"The caption says 'baron density' in the bottom panel; this should be 'baryon density'.","section":"Caption of Fig. 12"},{"comment":"The conclusions say ProSpect gives '≈3 times higher dust masses' than MAGPHYS, while §3.2 says the correction is '≈2.5 times'. Please reconcile these numbers or clarify that 3 refers to the uncorrected code comparison and 2.5 to the adopted correction.","section":"§7, item (iii)"},{"comment":"The opacity coefficient discussion would benefit from a quantitative statement of how much of the factor-of-three offset remains after applying the variable DTH correction, since the paper currently leaves the reader with two partially degenerate explanations for the ProSpect-MAGPHYS offset.","section":"§3.3, opacity discussion"}],"recommendation":"major_revision","confidential_remarks":"The paper is well within the scope of MNRAS and the 5 per cent baryon fraction is likely robust. The main risk is that the CDMH/CGMH quantitative claims rest on a two-parameter calibration and a prior that are not propagated into the quoted errors. I would send the manuscript back for a sensitivity analysis rather than reject it."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Short version: this is a solid, useful measurement paper that does something new — a single-survey-consistent census of stars, dust, neutral gas, and SMBHs — but the absolute scale of the dust and gas histories is set by a calibration choice that carries more weight than the error bars admit. The headline \"≈5 per cent of baryons in galaxies\" is robust; the CDMH and CGMH shapes are less so.\n\nWhat's genuinely new: they combine ~800,000 ProSpect SED fits from GAMA and DEVILS to produce redshift-resolved stellar, dust, and neutral-gas mass functions, then integrate to cosmic histories. That is a real step beyond prior literature, which mixed codes, surveys, and fitting assumptions. The LSS correction is reasonable, the comparison to simulations is informative, and the paper is clearly written. The authors are unusually explicit about their systematics — they state in §3.2 that the scaling is sensitive to q and that q=0.1 gives 3.1× lower dust masses. Credit where due.\n\nNow the soft spots, in proportion. The global ≈2.5 dust down-scaling is calibrated on 218 bright, local, FIR-detected galaxies, then applied uniformly to the whole sample, including the ~99% of DEVILS galaxies at z>2 without FIR detections. For those, the dust mass is controlled by a Gaussian prior on α. The paper shows in Fig. 2 that adding FIR shifts dust masses by ~0.7 dex, so the high-redshift CDMH points are effectively prior-dominated. That scale uncertainty is not propagated into Table A5, where the quoted errors are ~0.05 dex. The neutral-gas history, being dust mass divided by a metallicity-dependent DTG, inherits the same scale problem — which means the ~0.6 dex deficit versus 21cm measurements is not a purely astrophysical statement. Also, the agreement with MAGPHYS-based literature is by construction, since the scaling was chosen to match MAGPHYS; that's circular and should be acknowledged more directly. One minor inconsistency: the abstract says 0.7 dex lower than 21cm, the body says 0.6.\n\nNone of this kills the central claim. Stars dominate the baryon budget in galaxies, so the 5% figure survives even a factor of 3 in dust. The paper is honest about its weaknesses. I'd send it to a knowledgeable referee rather than desk reject. A serious referee should push for a per-object treatment of the variable DTH (or at least a systematic error term for q and the α prior), and for a clear statement that the CDMH/CGMH normalization is calibration-limited, not random-error-limited. With those revisions, this would be a reference point for the field. For a reading group, it's actually a great case study in how SED-fitting systematics percolate through to cosmic inventories.","headline":"A genuinely useful self-consistent baryon census from GAMA+DEVILS, but the dust-mass scale calibration is too fragile to trust the quantitative CDMH/CGMH without caveats.","tokens_in":25776,"tokens_out":2158,"would_cite":true,"duration_ms":24714,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":["98.62.-g"],"model":"deepseek-v4-flash","headline":"Using spectral energy distribution fits to about 800,000 galaxies, this paper argues that stars, dust, neutral gas, and supermassive black holes inside galaxies account for only about 5% of the universe's baryons.","keywords":["cosmic baryon inventory","cosmic dust mass history","neutral gas","supermassive black holes","spectral energy distribution fitting","ProSpect","galaxy surveys","dust-to-gas ratio"],"falsifier":"Measure dust masses for a sample of faint, high-redshift galaxies using far-infrared or submillimeter data that directly constrain the cold-dust component (e.g., ALMA), without imposing the q=0.14 scaling. If these directly constrained dust masses are systematically about 2.5 times higher than the scaled ProSpect values, the global correction is over-applied and the 5% figure is too low; if they agree, the absolute scale is supported.","tokens_in":24722,"feed_emoji":"🌌","tokens_out":5638,"duration_ms":54927,"temperature":0.7,"pith_summary":"This paper builds a self-consistent census of the baryons confined inside galaxies over the last 12 billion years, using SED fits to about 800,000 galaxies from two large surveys. It finds that stars, dust, neutral gas, and supermassive black holes within the optical radii of galaxies add up to about 5% of the cosmic baryon budget at z=0, rising from roughly 1% at z≈3. The cosmic dust mass history peaks at z≈1–2 and declines more slowly than the cosmic star formation history, and the dust-traced neutral gas density is about 0.6 dex lower than 21-cm HI measurements. A sympathetic reader would take this as the first homogeneous, data-driven accounting of galaxy-bound baryons that can be compared directly against simulations and against searches for the ionized 'missing' baryons.","feed_headline":"Galaxies hold just 5% of all baryons","feed_subtitle":"A census of 800,000 galaxies shows the rest is ionized gas spread between galaxies.","key_machinery":"The argument is carried by ProSpect, an SED-fitting code that enforces energy balance between stellar attenuation (Charlot & Fall) and dust re-emission (Dale et al.), yielding a dust mass for every galaxy. Because ProSpect's default constant dust-to-hydrogen ratio produces dust masses about 2.5 times higher than the MAGPHYS code, the authors apply a wavelength-dependent dust-to-hydrogen weighting with a PAH+very-small-grain mass fraction of q=0.14, calibrated on 218 bright far-infrared-detected galaxies, to bring ProSpect into agreement with MAGPHYS. A metallicity-dependent dust-to-gas ratio (from Rémy-Ruyer et al.) then converts dust to neutral gas, and double Schechter function fits to the","core_discovery":"The central claim is that galaxies as bounded systems contain only about 5% of the universe's baryons. The authors derive this by fitting FUV-to-FIR spectral energy distributions with the ProSpect code to obtain stellar and dust masses for ~800,000 galaxies in GAMA and DEVILS at 0