{"id":"7fb9f7f8-01cf-4392-a09b-e5e6069875a0","arxiv_id":"2509.03189","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":3,"one_line_summary":"HAWC's Pass 5 analysis of 8 years of data yields new TeV diffuse galactic emission profiles with tails beyond 3 degrees latitude and a galactic-center excess relative to standard cosmic-ray propagation models.","lead":"HAWC used 8 years of reprocessed data to map the Milky Way's diffuse TeV gamma-ray glow after removing known sources. The new profiles show emission far from the galactic plane and an excess toward the galactic center, and broadly match LHAASO's measurements.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Source-subtraction degeneracy is the load-bearing risk: the CTAO-style algorithm may absorb or inject diffuse flux, and the two threshold variants do not bracket this model error.","rationale":"The reader's weakest_assumption identifies the same central risk: the source-subtraction algorithm must fully account for non-diffuse emission for the residuals to be interpreted as diffuse. This is indeed the most load-bearing assumption in the paper. The two threshold variants used to estimate source-model uncertainty do not address the deeper degeneracy between extended source models and diffuse templates, nor do they quantify unresolved-source contamination. The lack of explicit significance statements further weakens the central claims. However, the paper itself acknowledges these limitations, presents a second mask-based analysis that broadly agrees with LHAASO, and labels the results as preliminary. Thus the concern does not warrant rejection; it does warrant maintaining the CONDITIONAL verdict. The proposed test—comparing latitude tails from the mask-based analysis without source subtraction—would directly isolate whether the tails are an artifact of source subtraction, which is the key unresolved question.","tokens_in":8413,"tokens_out":2954,"duration_ms":40524,"concrete_test":"Recompute the latitude profile in the 20°<l<60° band using the mask-based LHAASO-style analysis (no source subtraction) extended to |b|<10°, and compare the |b|=3°–10° flux with the source-subtracted profile from Figure 3. If the mask-based profile also shows excess over the CRINGE/Uniform/IEM templates at |b|>3°, the tail claim is independent of source subtraction; if not, the source-subtraction degeneracy is the likely origin of the claimed tails.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim—that residual emission after source subtraction is genuinely diffuse and extends beyond |b|=3°—requires that the fitted source model neither absorbs real diffuse emission nor leaves unresolved source flux in the residuals. The CTAO-style workflow detects 3σ local maxima in maps that already contain the diffuse emission and fits them with generalized Gaussians. This creates a degeneracy: compact or low-surface-brightness components of the diffuse emission can be fitted as 'sources', while imperfectly modeled sources can leave residuals that masquerade as diffuse flux. The paper's own admission of imperfect fits near Crab and Geminga shows the geometric spatial models are not adequate for very bright sources, and such mismodeling can bias residuals on degree scales. The two source-model thresholds only vary the selection threshold and association requirement; they do not bracket morphological mis-modeling, source-template degeneracy, or the effect of unresolved source populations. Additionally, the word 'significant' is never quantified—no test statistic, significance map, or p-value supports the headline claims of significant remaining emission or significant >3° tails. The qualitative plots and error bands are suggestive but do not establish the claim at the level asserted.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This conference paper presents an 8-year HAWC (Pass 5) analysis of TeV Galactic diffuse gamma-ray emission. The authors subtract a catalog of point-like/extended sources using a CTAO-style detection and fitting algorithm, then fit the residual emission with three Galactic diffuse emission templates (CRINGE with rescaled X_CO, IEM-varmin-rescaled, and Uniform CR). They report longitudinal and latitudinal flux profiles with statistical, source-model, and template uncertainties, and find significant remaining emission throughout the Galactic plane, non-Gaussian latitude tails out to |b|=10 deg, and an excess toward the Galactic center relative to the CRINGE prediction. They also reproduce the LHAASO analysis in inner and outer windows and report broadly consistent spectra, with a ~50% higher inner-window normalization attributed to mask differences.","tokens_in":8714,"tokens_out":4452,"duration_ms":53837,"significance":"If the claims hold, this would be an important, independent TeV measurement of the Galactic diffuse emission from HAWC, especially the latitude tails beyond 3 deg and the inner-Galaxy excess. The analysis is more careful than typical conference proceedings: it uses state-of-the-art data processing (Pass 5), an open-source tool (Gammapy), and explicitly treats three classes of uncertainty (statistical, source model, template). The cross-check against LHAASO with an equivalent analysis method is a useful consistency test. However, the central scientific claims rest on qualitative significance assertions and on a source-subtraction systematic that is only partially bracketed, so the current manuscript is not yet suitable as a definitive measurement.","major_comments":[{"comment":"The abstract and Section 3.1 assert 'significant remaining emission throughout the Galactic plane' and 'significant emission beyond 3 degree latitude', but no test statistic, p-value, or significance map for the residual after source subtraction is provided. The lower panels of Fig. 1 are residual significance maps, but they are not per-longitude-bin or per-latitude-bin significances and do not quantify the tail claim. Please define 'significant' and report a quantitative measure (e.g., TS or p-value) for the >3 deg emission and for the inner-Galaxy excess relative to the models.","section":"Section 3.1, Figs. 2 and 3"},{"comment":"The source-model systematic is estimated from only two selection thresholds (all 3-sigma sources vs. sources with >=4 sigma or catalog association). This does not bracket the dominant degeneracy: the source-detection map already contains the diffuse emission, so compact diffuse structures can be absorbed as 'sources', while imperfectly modeled bright sources (as acknowledged for Crab and Geminga) can inject residual flux on degree scales. The claim that 'the presence of the tails ... is independent of the source model assumed' is therefore not established. A cross-check using a mask-based source exclusion (as in the LHAASO comparison) or an explicit unresolved-source population model would materially strengthen the paper.","section":"Section 2.2 and 3.1"},{"comment":"The latitude-tail claim is based on a single longitude window, 20 deg < l < 60 deg, yet the abstract and conclusions state it as a general property of the Galactic diffuse emission. The longitude profile is integrated over |b|<10 deg and cannot confirm the tail beyond 3 deg elsewhere. Either restrict the claim to the measured range or show similar profiles for additional longitude bins (e.g., inner Galaxy and Cygnus), where source confusion and exposure differ significantly.","section":"Section 3.1, Fig. 3"}],"minor_comments":[{"comment":"Typos: 'singificant' should be 'significant'; 'Miky Way' should be 'Milky Way'.","section":"Section 1"},{"comment":"The phrase 'multiplied in each longitude bin by the best-fit normalization' is ambiguous. Clarify whether the normalization is an independent fit parameter per bin or a smooth function, and how this relates to the profile shown in Fig. 2.","section":"Fig. 1 caption and Section 2.2"},{"comment":"In Table 2, for the single power-law fit in the outer window, the columns gamma2 and E_br should be omitted or marked with an em dash rather than left blank, to avoid visually implying a broken power law.","section":"Tables 1 and 2"},{"comment":"The 50% higher inner-window normalization is attributed to mask differences, but no quantitative test is shown. If the [8] mask is not available, a statement that this is a plausible explanation rather than a demonstrated one would be more precise.","section":"Section 3.2"}],"recommendation":"major_revision","confidential_remarks":"This is a conference proceedings with the label 'Preliminary' on all figures. The central claims, particularly the >3 deg tail and the inner-Galaxy excess, go beyond what the current analysis quantitatively supports. The CRINGE model used as the main comparison is co-authored by the speaker; this is not a problem per se, but the paper should explicitly note the comparison-model provenance. The paper fits the scope of an astroparticle-physics conference but would need substantial strengthening before journal publication."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Quick take: this is a genuinely useful, preliminary HAWC measurement of TeV Galactic diffuse emission. It is more careful than the average ICRC proceedings: the Pass 5 data, the explicit six-way systematic treatment (two source models × three templates), and the fair attempt to reproduce the LHAASO analysis give the longitude/latitude profiles real weight. The main weakness is that 'significant' never gets a number—no test statistic, no significance map, no p-value—so the headline claims outrun the displayed evidence.\n\nWhat is actually new: the Pass 5 residual flux profiles in longitude and latitude are new measurements. The CTAO-style source subtraction adapted to HAWC is a genuine technical increment. The LHAASO comparison is the right thing to do: the outer-window consistency is reassuring, and the inner-window 50% normalization offset is plausibly traced to the different source mask, though that explanation is not quantified. The paper also openly identifies the fragile regions: Geminga/Monogem, Cygnus, and the inner Galaxy, where the source model uncertainty is largest. That honesty is real.\n\nSoft spots, in order. First, the source-model systematics are bracketed by only two threshold variants; that does not capture the more dangerous systematic of the geometric model absorbing or mis-assigning diffuse flux on degree scales. The statement that the >3° tails are independent of the source model is therefore weaker than it sounds, since only two variants were tried. The residual overfluctuations near Crab and Geminga confirm that the spatial models are imperfect for bright sources, and that can bias residuals on the scales of interest. Second, the missing significance quantification is fixable and typical for this venue, but it matters for the core claim. Third, no data release or code release, and the paper is explicitly preliminary. None of this makes the analysis look fraudulent; it just means the quantitative rigor is a notch below what a journal referee would need.\n\nWho gets value: anyone working on TeV Galactic diffuse emission or cosmic-ray transport, and the paper is a solid comparison point against LHAASO. I would bring it to a reading group. If the authors submit to a refereed journal, I would send it to review, with the request that they add significance calculations and broaden the source-model systematics. As a proceedings paper it is already a fair contribution.","headline":"Useful preliminary HAWC profiles of TeV diffuse emission; new Pass 5 data and a fair LHAASO comparison, but the 'significant' claims need numbers and the source-subtraction systematics are only partially bracketed.","tokens_in":9207,"tokens_out":4266,"would_cite":true,"duration_ms":44707,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"The Milky Way's TeV gamma-ray glow extends far beyond the narrow galactic plane, according to a new analysis of eight years of HAWC data.","keywords":["Galactic diffuse gamma-ray emission","TeV gamma rays","cosmic-ray propagation","HAWC","Galactic plane survey","source subtraction","LHAASO comparison","interstellar gas"],"falsifier":"A future instrument with better angular resolution could test whether the apparent diffuse emission at |b| > 3 degrees resolves into known or new point sources; if so, the gas-correlated diffuse claim weakens. Concretely, running this source-subtraction pipeline on mock skymaps with a known diffuse component plus realistic unresolved-source populations would reveal whether the recovered latitudinal tails are biased by source leakage.","tokens_in":8302,"feed_emoji":"🌌","tokens_out":3804,"duration_ms":46103,"temperature":0.7,"pith_summary":"The paper reports that the Milky Way's diffuse TeV gamma-ray emission—produced when cosmic rays collide with interstellar gas—is not confined to the thin galactic plane. After fitting and subtracting a catalog of sources, significant residual emission remains all along the plane and extends in broad, non-gaussian tails out to at least 10 degrees of galactic latitude. The shape of those tails matches expectations for cosmic rays interacting with atomic gas that rises hundreds of parsecs from the plane. Toward the galactic center, the measured flux exceeds predictions from conventional propagation models, hinting at extra cosmic-ray sources, a radial gradient, or unresolved faint sources. An independent analysis that mimics a recently published LHAASO-style mask recovers consistent spectra, lending confidence to the result.","feed_headline":"TeV glow reaches 10 degrees off the Milky Way's plane","feed_subtitle":"Eight years of HAWC data show diffuse gamma rays beyond 3 degrees latitude and an excess toward the galactic center.","key_machinery":"The source-subtraction workflow is the central mechanism: candidate sources are identified from significance maps at two correlation radii, merged if overlapping, and fit with generalized-Gaussian spatial models and log-parabola spectra, then subtracted from the data. The remaining emission is modeled with three diffuse templates—the CRINGE hadronic model with rescaled CO-to-H2 conversion, a Fermi-tuned variable-diffusion model, and a uniform-cosmic-ray model—and the spread across six fits (two source models, three templates) defines the systematic uncertainty bands.","core_discovery":"Using eight years of reprocessed Pass 5 data from a high-altitude water-Cherenkov observatory, the authors subtract a fitted source model—built with the automated workflow planned for a future Galactic Plane Survey—from maps of the TeV sky. The leftover emission is then fitted with three templates for the diffuse emission. The central finding is that this residual diffuse emission is significant across the Galactic plane and shows non-gaussian latitudinal tails out to |b| = 10 degrees, consistent with gas-correlated emission. The overall flux is higher than predicted by conventional models such as CRINGE, with the excess strongest toward the inner Galaxy. Spectral fits in inner and outer gal","pith_inferences":["If the inner-Galaxy excess is partly unresolved sources, a deeper survey with higher angular resolution should resolve a portion of the reported diffuse flux into point sources, shifting the excess downward.","The latitudinal tails could be used to constrain the scale height of cosmic rays and gas in the inner Galaxy when combined with atomic and molecular gas maps, offering a direct probe of propagation perpendicular to the disk.","The same source-subtraction pipeline could be applied to simulated skymaps with a known diffuse component to calibrate the systematic bias introduced by source-diffuse confusion, providing a quantitative correction for future analyses."],"forward_implications":["Diffuse TeV emission extends at least 10 degrees from the Galactic plane, with non-gaussian tails whose shape matches cosmic-ray interaction with interstellar gas.","The excess toward the Galactic center is larger than conventional models predict, implying either a more centrally peaked cosmic-ray source distribution, a radial gradient in accelerator properties, non-standard propagation, or unresolved faint sources.","The HAWC spectra in the LHAASO-defined inner and outer windows are consistent with LHAASO results where the analysis methods are matched, supporting the robustness of the diffuse-emission measurement.","The presence of the |b| > 3 degree tails is independent of the source model assumed, strengthening the claim that the extended emission is genuine.","The latitudinal and longitudinal flux profiles provide a new benchmark for TeV Galactic diffuse models, comparable in scope to what Fermi-LAT established at GeV energies."],"supporting_citations":[{"why":"The previous HAWC diffuse-emission analysis that this work extends with more data and updated processing.","marker":"[9]"},{"why":"Provides the CRINGE model, the conventional diffuse-emission prediction against which the measured profiles are compared.","marker":"[13]"},{"why":"Supplies the source-modeling workflow adapted from the prospective CTAO Galactic Plane Survey and the IEM-varmin-rescaled diffuse template.","marker":"[20]"},{"why":"The LHAASO measurement whose source mask and analysis regions are reproduced for the comparison analysis.","marker":"[7]"},{"why":"The LHAASO spectrum and broken-power-law model used for one-to-one parameter comparison in the inner and outer windows.","marker":"[8]"},{"why":"The Pass 5 data processing that provides the improved event reconstruction and gamma-hadron separation underlying the dataset.","marker":"[15]"},{"why":"The background-modeling technique that masks the Galactic plane to avoid absorbing diffuse emission into the hadron background.","marker":"[17]"}],"fun_headline_variants":["TeV diffuse glow extends 10° above Milky Way plane","HAWC's 8-year map reveals extra diffuse TeV emission","Diffuse TeV rays exceed model predictions across Galaxy","New HAWC analysis shows TeV emission far off plane","Galactic TeV glow higher than models, HAWC finds"],"cache_read_input_tokens":2688,"weakest_assumption_plain":"The fitted source catalog fully accounts for every compact and extended object in the field, so that whatever remains after subtraction is genuinely diffuse emission rather than misattributed source flux.","fun_headline_variants_meta":{"raw":{"variants":["TeV diffuse glow extends 10° above Milky Way plane","HAWC's 8-year map reveals extra diffuse TeV emission","Diffuse TeV rays exceed model predictions across Galaxy","New HAWC analysis shows TeV emission far off plane","Galactic TeV glow higher than models, HAWC finds"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.0006,"raw_usage":{"total_tokens":2637,"prompt_tokens":740,"completion_tokens":1897,"prompt_tokens_details":{"cached_tokens":256},"prompt_cache_hit_tokens":256,"prompt_cache_miss_tokens":484,"completion_tokens_details":{"reasoning_tokens":1813}},"tokens_in":484,"tokens_out":1897,"duration_ms":14158,"temperature":1.0,"reasoning_tokens":1813,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-05T11:05:54.808065+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A future instrument with better angular resolution could test whether the apparent diffuse emission at |b| > 3 degrees resolves into known or new point sources; if so, the gas-correlated diffuse claim weakens. Concretely, running this source-subtraction pipeline on mock skymaps with a known diffuse component plus realistic unresolved-source populations would reveal whether the recovered latitudinal tails are biased by source leakage.","supporting_citations":[{"cited_title":"J.961(2024) 104 [2310.09117]","cited_arxiv_id":null,"evidence_quote":"The previous HAWC diffuse-emission analysis that this work extends with more data and updated processing."},{"cited_title":"Performance of the HAWC Observatory and TeV Gamma-Ray Measurements of the Crab Nebula with Improved Extensive Air Shower Reconstruction Algorithms","cited_arxiv_id":"2405.06050","evidence_quote":"The Pass 5 data processing that provides the improved event reconstruction and gamma-hadron separation underlying the dataset."},{"cited_title":"Validation of standardized data formats and tools for ground-level particle-based gamma-ray observatories","cited_arxiv_id":"2203.05937","evidence_quote":"The background-modeling technique that masks the Galactic plane to avoid absorbing diffuse emission into the hadron background."}],"review_version":1}