{"id":"e9e47d7d-dcd6-440d-8353-88a25ecc599f","arxiv_id":"2501.18692","paper_version":2,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"In 2,009 type-2 AGNs, [O III] area correlates with AGN luminosity, and objects with and without outflow signatures have statistically identical area-luminosity relations.","lead":"Astronomers used ordinary survey images to measure the glowing gas clouds around 2,009 active black holes and found that outflows do not make these clouds larger. The cloud size tracks the black hole's brightness instead, pointing to photoionization as the main influence.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Outflow classification from the 3″-fiber σ[O III]/σ⋆ ratio does not sample the gas that sets the measured [O III] area, so the null may be an aperture artifact.","rationale":"The paper's own text flags the relevant gaps: §3.4 excludes emission beyond 5″ from the continuum center and notes the possible loss of light echoes; §5.3 admits that low-S/N single-Gaussian outflows may be missed; and §6.3 cites outflow/NLR size ratios of 0.22–0.72, implying the fiber-based outflow probe is not measuring the same gas whose area determines the result. That makes the aperture-mismatch concern load-bearing rather than stylistic. It is not an internal inconsistency, and the null result is consistent with previous IFU studies, so this should not flip the verdict to rejection. The proposed MaNGA-based check directly tests whether the two subsamples are cleanly separated in the region that defines the measured area. Until such a check is done, the causal wording 'photoionization, not outflows' in §5.4 and the Summary remains conditional. The reader already reached CONDITIONAL; this stress-test supports that verdict rather than changing it.","tokens_in":18302,"tokens_out":7234,"duration_ms":75301,"concrete_test":"Use the MaNGA overlap of this sample (the authors already use MaNGA data in §3.5) and redo the comparison with spatially resolved [O III] kinematics. Classify a galaxy as outflowing only if σ_[O III] exceeds the local stellar σ by the same factor in pixels at radii beyond the SDSS 3″ fiber, and also classify by the spatial extent of the broad wing. Then compare residual [O III] area at fixed L_bol,15µm in 0.5-dex luminosity bins between resolved-outflow and resolved-no-outflow galaxies. If an area difference appears under resolved classification, the paper's null is an aperture artifact; if it remains absent, the central claim survives this check.","verdict_should_be":"UNCHANGED","load_bearing_attack":"For the central claim to hold, the outflow and no-outflow subsamples must genuinely differ in the kpc-scale kinematics of the gas whose area is being measured. The outflow assignment in §5.3 uses the SDSS 3″-diameter fiber (6.0–14.5 kpc at these redshifts) and Eq. (4), assuming σ_[O III]² = σ_gr² + σ_non-gr² with σ_gr = σ⋆ and a σ_[O III]/σ⋆ > 1.4 threshold. The [O III] areas measured in §3.4, however, reach 3.7–224 kpc² and are dominated by faint extended gas outside the fiber. A central fiber spectrum cannot tell whether that outer gas is outflowing; if outflows are centrally concentrated, as the paper itself notes from Fischer et al. (2018), Kim et al. (2023), and Polack et al. (2024), then a null correlation between central fiber kinematics and total NLR area is expected even when outflows influence the extended NLR. This is compounded by the luminosity mismatch between subsamples (KS p<0.01 in Figure 12) and the luminosity-dependent detection fraction (Figure 13), so the comparison in §5.4 cannot separate 'outflows do not affect NLR size' from 'we did not classify the gas that sets the size.'","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper constructs [O III] λ5007 emission-line images for 2,724 SDSS type-2 AGNs at 0.13 1.4 (Eq. 4). The central claim is that the [O III] area–luminosity relation is the same for objects with and without outflows, so outflows do not affect the NLR size and photoionization is the dominant driver.","tokens_in":18611,"tokens_out":3388,"duration_ms":37010,"significance":"If the main claim holds, the result is astrophysically meaningful: it would show, with a much larger sample than previous IFU studies, that mechanical AGN feedback does not inflate the NLR at moderate luminosities. The paper also demonstrates a cheap broadband-imaging technique that can be applied to large photometric surveys, and it includes useful calibration checks, such as the MaNGA-based simulation of the Hβ contamination (Section 3.5) and a comparison with Sun et al. (2018). However, the central inference is currently not established because the outflow classification is made from a central aperture that does not sample the gas whose area is measured, and the subsample comparison is not controlled for the strong luminosity difference between outflow and no-outflow objects.","major_comments":[{"comment":"The outflow classification uses the SDSS 3-arcsec fiber spectrum (physical diameter 6.0–14.5 kpc), while the [O III] areas measured in Section 3.4 extend up to 224 kpc² and are dominated by fainter, more extended gas. Equation (4) and the σ[O III]/σ* > 1.4 criterion therefore characterize only the central kiloparsecs of gas, not the gas that sets the measured isophotal area. If outflows are centrally concentrated, as the paper itself notes in Section 6.3 from Fischer et al. (2018), Kim et al. (2023), and Polack et al. (2024), then a null correlation between the fiber-based outflow flag and the total NLR area is expected even when outflows influence the extended NLR. The central claim in Section 5.4 and the Summary thus requires either spatially resolved kinematics of the extended gas or an explicit demonstration that the 3-arcsec fiber samples the same gas that dominates the area measurement.","section":"§5.3 vs §3.4"},{"comment":"The comparison between the outflow and no-outflow subsamples is not controlled for AGN luminosity. The authors report a KS p<0.01 for the Lbol distributions of the two subsamples, yet they compare the raw [O III] area distributions and the slopes of two separate fits. Similar slopes do not establish that the NLR size is the same at fixed luminosity; the intercepts, the luminosity ranges, and the scatter matter. A luminosity-matched control sample, an analysis of area residuals from the global area–luminosity relation, or a binned comparison in Lbol is needed before the statement 'at the given luminosity, the objects with and without outflows exhibit the same extension' can be supported.","section":"§5.4, Figure 12"},{"comment":"The measured area–luminosity relation is strongly dependent on the adopted isophotal threshold: changing from 1.4e-15 to 3e-15 erg/s/cm2/arcsec2 changes the slope from 0.27 to 0.39 and Pearson's r from 0.31 to 0.52. In addition, the [O III] detection fraction increases with luminosity and with the chosen threshold, and 588 objects were excluded because no [O III] emission was recovered. Because the outflow subsample is more luminous, both the threshold dependence and the luminosity-dependent detection fraction can bias the relative areas of the two subsamples. The outflow comparison should be repeated at the same brighter isophote used in Figure 14, and the excluded objects should be accounted for (e.g., with survival-analysis methods) rather than simply dropped.","section":"§6.2 and Figure 13"},{"comment":"The decomposition σ²[O III] = σ²_grav + σ²_non-grav with σ_grav = σ* assumes that all excess line broadening above the stellar dispersion is an outflow signature. Broadening from turbulence, radiation pressure, unresolved multiple kinematic components, or a different stellar–gas kinematic relation would also produce σ[O III]/σ* > 1.4. The threshold of 1.4 additionally assumes equal contributions of the two terms in quadrature. This assumption is common in the literature but should be validated for the present sample, for example by checking the outflow classification against objects with IFU observations or against a kinematic criterion based on the wing component from the double-Gaussian fits.","section":"§5.3, Eq. (4)"}],"minor_comments":[{"comment":"The abstract contains a typo: 'AGNS' should be 'AGNs.'","section":"Abstract"},{"comment":"The caption mentions 'the density map in the middle panel,' but the figure appears to have only a central scatter plot with a color density representation; please clarify or relabel the panels.","section":"Figure 8"},{"comment":"The power-law fit used to derive the continuum ratio Θ is described only briefly; please state the spectral fitting range and whether emission-line pixels were masked.","section":"§3.1"},{"comment":"Equation (3) defines the non-parametric linewidth Δλ, but the text then refers to ΔV[O III] without explicitly giving the conversion; please write the conversion to velocity units.","section":"§4"},{"comment":"The statement that outflow sizes are usually smaller than NLR sizes with ratios 0.22–0.72 would benefit from specifying whether these are ratios of radii or areas, since the quoted range differs across the cited studies.","section":"§6.3"}],"recommendation":"major_revision","confidential_remarks":"The paper addresses an interesting question and leverages a large SDSS sample, but the central null result is currently not convincing because of the aperture mismatch between the fiber-based outflow classification and the image-based NLR sizes, and because the subsample comparison is not luminosity-controlled. These are fixable with additional analysis rather than new observations. I would be willing to review a revised version."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"You should know two things about this paper. First, it is the first large-sample statistical comparison of NLR isophotal areas between type-2 AGNs with and without outflow signatures selected from [O III] kinematics, and that is a legitimate step forward. Second, the outflow diagnostic is measured from the SDSS 3″ fiber, while the [O III] area is dominated by faint gas far outside that fiber, so the null result is less decisive than the authors claim.\n\nThe paper does several things well. The broadband [O III] imaging technique is carefully executed: PSF matching, Monte Carlo uncertainties, and a simulation showing Hβ contamination is small. The sample of 2,009 objects is much larger than the 300 in Sun et al. (2018), and the area–luminosity relation they recover is consistent with that work, especially when the brighter isophote is used. The null result on outflow effects also agrees with earlier IFU and long-slit studies (Fischer et al. 2018; Kim et al. 2023; Polack et al. 2024). That consistency is worth something.\n\nThe soft spots are real but not fatal. The main one is the aperture mismatch. The outflow classification uses σ[O III]/σ⋆ from the 3″ fiber, which samples the central 6–14.5 kpc, while the measured [O III] areas extend out to 3.7–224 kpc² and are set by faint extended gas. If outflows are centrally concentrated—as the authors themselves note from the literature—then this test is not very sensitive. The paper overinterprets a null as evidence that photoionization, not outflows, sets NLR size. A more careful statement would be that outflow signatures in the central fiber do not correlate with total NLR extent.\n\nSecond, the outflow and no-outflow subsamples are not luminosity-matched. The KS test shows their Lbol distributions differ (p<0.01), and the best-fit slopes are compared without binning into common luminosity ranges. A luminosity-binned comparison, or an analysis that matches the samples, would make the claim much stronger. The luminosity-dependent detection fraction (their Figure 13) compounds this.\n\nThird, the area-luminosity slope is threshold-dependent (0.27 to 0.39, r 0.31 to 0.52). The authors acknowledge this and compare with Sun et al. (2018), so it is not a hidden flaw, but it means the single-threshold comparison in the outflow analysis is a limited look.\n\nWho is this for? Observers working on AGN feedback and the NLR size–luminosity relation. It deserves a serious referee. The analysis is careful, the sample is large, and the null is a useful data point. But the paper needs revision before acceptance: address the aperture issue explicitly, add luminosity-binned or matched comparisons, and soften the causal phrasing.\n\nMy recommendation: send it to peer review with the expectation of major revision.","headline":"A useful large-sample null result on outflows and NLR size, but the fiber-based outflow diagnostic and unmatched luminosities make the conclusion overreaching.","tokens_in":19145,"tokens_out":3305,"would_cite":false,"duration_ms":29785,"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":"This paper claims that gas outflows do not significantly change the spatial extent of the [O III]-emitting narrow-line region in type-2 AGNs, so the NLR size–luminosity relation is set by photoionization from the central engine rather…","keywords":["active galactic nuclei","narrow-line region","outflows","[O III] emission","broadband imaging","size-luminosity relation","SDSS","type-2 AGN"],"falsifier":"If a spatially resolved IFU study of a luminosity-matched sample found that galaxies with kinematically distinct outflow components have systematically larger [O III] isophotal areas than those without, or that the extra line width is produced by turbulence rather than outflows, the paper's central claim would fail.","tokens_in":18097,"feed_emoji":"🔭","tokens_out":9057,"duration_ms":68365,"temperature":0.7,"pith_summary":"This paper claims that gas outflows, detected as broadened [O III] emission, do not change the measured size of the narrow-line region (NLR) in type-2 active galactic nuclei. Using SDSS broadband images to reconstruct [O III] maps for 2,009 galaxies, the authors find that at a given AGN luminosity, galaxies with and without outflow signatures have indistinguishable [O III] areas and nearly identical size–luminosity slopes. The size of the NLR therefore appears to be set by photoionization from the central engine rather than by mechanical outflow feedback, at least in the moderate-luminosity regime studied. A sympathetic reader would care because this directly tests a key assumption behind AGN feedback models: that outflows inflate or deplete the ionized gas reservoir in the host galaxy.","feed_headline":"Outflows do not enlarge AGN narrow-line regions","feed_subtitle":"A 2,009-galaxy SDSS study finds NLR size tracks AGN luminosity, not outflow state, questioning mechanical feedback.","key_machinery":"The central machinery is a broadband-excess technique: subtracting a PSF-matched i- or z-band continuum image from the SDSS r-band image isolates the emission-line flux, which is rescaled by the spectral ratio $\\gamma_{5007}$ to produce a pure [O III] map whose isophotal area is measured down to $1.4\\times10^{-15}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$. The outflow diagnostic is Eq. (4), $\\sigma_{[\\rm O\\,III]}^2 = \\sigma_{\\rm gr}^2 + \\sigma_{\\rm non-gr}^2$, with $\\sigma_{\\rm gr} = \\sigma_\\star$, so a ratio $\\sigma_{[\\rm O\\,III]}/\\sigma_\\star > 1.4$ marks a non-gravitational (outflow) component equal to the gravitational one. The claim rests on comparing the area–luminosity relations of the two subsamples.","core_discovery":"The paper establishes a null result: the presence of an outflow does not significantly affect the extension of the [O III] λ5007 emission, so the NLR size–luminosity relation is independent of outflow state. The [O III] areas of outflow and non-outflow subsamples, selected by $\\sigma_{[\\rm O\\,III]}/\\sigma_\\star > 1.4$ from SDSS fiber spectra, follow the same best-fit slope ($0.21\\pm0.03$ versus $0.19\\pm0.03$) against bolometric luminosity, and their area distributions are statistically consistent. Since the area–luminosity correlation ($r\\sim0.3$) is much stronger than the area–velocity-dispersion correlation ($r\\sim0.12$), the authors conclude that photoionization from the central AGN, not outflow kinematics, determines the spatial extent of the NLR.","pith_inferences":["Editorial inference: if outflows do not set NLR extent, the [O III] area at fixed luminosity is a cleaner photoionization luminosity indicator than the [O III] line width, which mixes gravitational and non-gravitational kinematics.","Editorial inference: the null result suggests the extended gas is pre-existing in the host and lit up by the AGN, so distant [O III] emission may trace past (flickering) luminosity rather than current outflow transport.","Editorial inference: a direct test would measure outflow extent with IFU observations of a matched subsample; the paper's picture predicts outflow size is typically 0.2–0.7 times the NLR size, consistent with the cited outflow-size studies.","Editorial inference: the threshold dependence of the slope implies that single-epoch broadband size measurements need surface-brightness correction before being used as standard rulers or distance indicators."],"forward_implications":["If the null result holds, the NLR size–luminosity relation can be treated as a photoionization scaling law that is unaffected by outflow activity.","Mechanical AGN feedback does not inflate the NLR at luminosities of $10^{43}$–$10^{46}$ erg s$^{-1}$, so models that require outflows to push ionized gas to large radii need revision in this regime.","Outflow diagnostics (broad [O III] wings, high $\\sigma_{[\\rm O\\,III]}/\\sigma_\\star$) and NLR extent decouple: a galaxy can show strong outflow kinematics without a larger ionized region.","The measured slope of the size–luminosity relation depends strongly on the isophotal surface-brightness threshold, so comparisons across surveys must use matched thresholds.","Broadband imaging of large SDSS samples can substitute for IFU surveys in statistical studies of NLR sizes, enabling samples of thousands instead of dozens."],"supporting_citations":[{"why":"Provides the broadband-excess technique for reconstructing [O III] images and the HSC-based size–luminosity relation used as the main comparison.","marker":"Sun et al. (2018)"},{"why":"Supplies the double-Gaussian fitting constraints and amplitude-to-noise criteria adopted for measuring [O III] kinematics and outflow signatures.","marker":"Woo et al. (2016)"},{"why":"Presents the opposing scenario that NLR gas clouds are transferred outward by outflows, which the paper explicitly tests and rejects.","marker":"Joh et al. (2021)"},{"why":"Gives a spectroscopically measured NLR size–luminosity relation against which the broadband areas are compared.","marker":"Liu et al. (2013)"},{"why":"Provides another deep-isophote size–luminosity slope used to interpret the threshold dependence of the correlation.","marker":"Hainline et al. (2013)"},{"why":"Measures outflow-to-NLR size ratios (0.22–0.72) with HST narrowband images, supporting the null result.","marker":"Polack et al. (2024)"},{"why":"Establishes the [O III] equivalent-width–luminosity relation used to explain the detection fraction of the broadband technique.","marker":"Zakamska et al. (2003)"}],"fun_headline_variants":["Outflow state doesn't set AGN narrow-line size","NLR size tied to AGN luminosity, not outflows","Outflows fail to inflate AGN narrow-line regions","2,000 AGNs show outflows don't stretch NLRs","AGN outflows: no effect on narrow-line region size"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The outflow classification assumes Eq. (4), namely that the non-stellar part of the [O III] line width is entirely outflow-driven with $\\sigma_{\\rm gr}=\\sigma_\\star$, and that the 3-arcsec SDSS fiber samples the gas that sets the overall NLR extent, so if the extra width comes from turbulence or the outflows lie outside the fiber, the subsamples are not cleanly separated.","fun_headline_variants_meta":{"raw":{"variants":["Outflow state doesn't set AGN narrow-line size","NLR size tied to AGN luminosity, not outflows","Outflows fail to inflate AGN narrow-line regions","2,000 AGNs show outflows don't stretch NLRs","AGN outflows: no effect on narrow-line region size"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000259,"raw_usage":{"total_tokens":1624,"prompt_tokens":1023,"completion_tokens":601,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":639,"completion_tokens_details":{"reasoning_tokens":516}},"tokens_in":639,"tokens_out":601,"duration_ms":4844,"temperature":1.0,"reasoning_tokens":516,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-09T22:47:44.752432+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"If a spatially resolved IFU study of a luminosity-matched sample found that galaxies with kinematically distinct outflow components have systematically larger [O III] isophotal areas than those without, or that the extra line width is produced by turbulence rather than outflows, the paper's central claim would fail.","supporting_citations":[{"cited_title":"L., Greene, J","cited_arxiv_id":null,"evidence_quote":"Gives a spectroscopically measured NLR size–luminosity relation against which the broadband areas are compared."},{"cited_title":"E., Revalski, M., Crenshaw, D","cited_arxiv_id":null,"evidence_quote":"Measures outflow-to-NLR size ratios (0.22–0.72) with HST narrowband images, supporting the null result."}],"review_version":1}