{"id":"b458b9fb-2621-4661-acf6-b12644197d35","arxiv_id":"2411.17500","paper_version":2,"verdict":"ACCEPT","confidence":"HIGH","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"After correcting for atmospheric seeing in deep MUSE data, the quasar F13451+1232 shows no fast (W80 > 500 km/s) galaxy-wide ionised outflow; the fast outflow is limited to the central 100 pc.","lead":"A fast gas outflow in a nearby merging galaxy that looked galaxy-wide is actually confined to about 100 parsecs from the quasar, once atmospheric blur is removed. The apparent large-scale outflow was an artifact of seeing, and correcting it cuts earlier estimated outflow power by 10 to 100 times.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"PSF-shape assumption for the nuclear outflow is the load-bearing step; the Moffat fit uses the same data it is asked to subtract, and a slightly extended or anisotropic nuclear outflow would masquerade as 'no extended outflow'.","rationale":"The reader correctly identifies the PSF-subtraction completeness as the weakest assumption. My concern is more specific: the Moffat profile is fitted to the nuclear-model flux distribution and then used to subtract that same distribution. This is a self-referential subtraction that can absorb genuine extended emission. The agreement between the fitted Moffat FWHM and the stellar PSF FWHM (0.74±0.02 vs 0.79±0.10) is within 1 sigma, but the comparison is not a full test of the PSF shape; the nuclear model has only two free amplitudes while a real extended outflow could have spatially varying kinematics. The reader's verdict (ACCEPT) is reasonable given the strong internal cross-checks, but the central claim hinges on a PSF model that is fit and subtracted using the same data. An independent check against HST imaging would settle whether the null result is robust. Therefore I recommend CONDITIONAL rather than REJECT, because the concern is specific but not yet demonstrated to fail. The paper is honest about its dependence on the PSF model, and my attack does not allege any internal inconsistency; it identifies a boundary condition that the authors should test explicitly.","tokens_in":28043,"tokens_out":1734,"duration_ms":16859,"concrete_test":"Cross-correlate the MUSE beam-smearing-corrected residual [O III] map (after the Moffat subtraction of Sec. 3.2.3) with the HST/ACS [O III] image of Tadhunter et al. (2018) at matching spatial resolution. If the residual MUSE emission at radii 0.5–3 arcsec has no counterpart in the HST image, the null result is robust; if there is residual MUSE emission that is absent in HST, then the extended emission was indeed removed by the PSF-subtraction assumption.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The central claim — that all fast (W80 > 500 km/s) [O III] emission outside the central ~100 pc is beam-smeared nuclear outflow — depends on the completeness of the PSF subtraction in Secs 3.2.3–3.2.4. The PSF is measured by fitting a single circular 2D Moffat function to the spatial distribution of the nuclear-model flux itself, then that same Moffat profile is subtracted from every spaxel. If the true nuclear outflow is slightly extended (a few hundred pc) but fitted as a point source, or if it has an anisotropic/elongated structure, the residual extended flux becomes part of the fitted PSF and is removed along with the seeing halo. The consistency of the fitted FWHM (0.74±0.02 arcsec) with the stellar PSF (0.79±0.10 arcsec) is encouraging but not decisive, because both the normalisation and the shape (a single circular Moffat) are forced. The residual map in Fig. 3 is claimed to show no structure, but the residuals are only shown to ±0.04 of the peak, and the fit itself absorbs any large-scale wings. The conclusion is also sensitive to the fixed relative amplitudes of the two broad nuclear components (Table 1): if the relative amplitude of the very broad component changes with radius, a genuinely extended, lower-velocity outflow could be modeled as a scaled copy of the nuclear model. The strongest independent check would be to compare the PSF-subtracted residual images with HST/ACS [O III] imaging (Tadhunter et al. 2018) at the same spatial scales, since HST is not limited by atmospheric seeing. Such a comparison would directly test whether any extended broad-wing emission is real or an artifact of the Moffat assumption.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper analyses archival VLT/MUSE-DEEP observations of the type-2 quasar/ULIRG F13451+1232 to test whether the fast warm-ionised AGN-driven outflow seen near the nucleus is also present on galaxy-wide scales. The authors construct a two-Gaussian 'nuclear model' from the central 0.4-arcsec aperture, then fit this fixed-shape model plus additional free Gaussians to each spaxel, and also fit a Moffat profile to the spatial distribution of the nuclear-model flux. The Moffat FWHM matches the seeing measured from a field star for both [O III] and H-alpha, and subtracting this PSF-scaled nuclear model removes the circular high-velocity region that appears in free fits. The resulting residual maps show only modest kinematics, which the authors interpret as gravitational motions in a merger. They further quantify that ignoring beam smearing would overestimate mass outflow rates by up to an order of magnitude and kinetic powers by one to two orders of magnitude.","tokens_in":28334,"tokens_out":11310,"duration_ms":105223,"significance":"The paper addresses a key controversy in AGN feedback observations: whether ground-based IFU measurements of high-velocity extended emission represent genuine galaxy-wide outflows or seeing artifacts. The main result, if it holds, is a strong, direct demonstration that beam smearing of a compact nuclear outflow can mimic a kpc-scale high-velocity outflow in a representative quasar/ULIRG, and that correcting for it removes the evidence for galaxy-wide outflows in this object. The analysis is careful: the PSF is cross-checked against an independent field star at two wavelengths, the free-fitting versus corrected cases are explicitly compared, and the derived upper limits on extended outflow energetics are presented transparently. These strengths make the paper a valuable methodological case study for the field.","major_comments":[{"comment":"The completeness of the PSF subtraction is the load-bearing step for the null result. The Moffat profile is fitted to the same nuclear-model flux distribution that is subsequently subtracted from each spaxel, and the residual map (right panel of Fig. 3) is displayed only over a ±0.04 range of the normalised peak, so any large-scale or asymmetric residuals that are absorbed by the fit would not be visible. I ask the authors to quantify the quality of the Moffat fit as a function of radius (e.g., radial profile with residuals in absolute flux units and a reduced chi-square) and to test explicitly whether an additional spatially extended component (e.g., a second Gaussian or Moffat) is statistically required by the nuclear-model flux distribution. Without this, the claim that all fast (W80 > 500 km/s) emission outside ~100 pc is beam-smeared nuclear emission is not fully established.","section":"Section 3.2.3, Fig. 3"},{"comment":"The nuclear model fixes the relative amplitudes of the two broad Gaussian components to the values fitted in the 0.4-arcsec nuclear aperture. This implies that any genuine extended emission whose line profile resembles the nuclear outflow — for example, a more spatially extended component with a different ratio of broad-to-very-broad flux — would be absorbed by the scaled nuclear model and would not appear in the residual kinematics. I recommend a robustness test in which the two nuclear components are allowed independent spatial scalings (separate Moffat FWHMs) in the spaxel fits; if the two components were found to require different FWHMs, that would indicate that the subtraction is removing an extended component rather than pure seeing. This test would directly address the circularity concern.","section":"Sections 3.2.1–3.2.2, Table 1"},{"comment":"The paper cites the HST/ACS [O III] imaging of Tadhunter et al. (2018) as evidence that the nuclear outflow is compact, but it does not use that image as a quantitative check of the PSF subtraction. A direct comparison of the PSF-subtracted MUSE [O III] image with the HST image at matched spatial scales would provide an independent, non-seeing-limited test of whether genuine extended [O III] emission is being removed. If the MUSE residuals match the HST structures, the null result would be much more robust; if not, the residual map would reveal the presence of extended flux that the current subtraction removes.","section":"Section 4.1 / Section 3.2.3"}],"minor_comments":[{"comment":"The text says 'T > 10^6 cm^{-3}' for the hot phase; the unit should be kelvin, not cm^{-3}, for temperature, so this is likely a typo.","section":"Section 4.4"},{"comment":"The residual panel would be more informative if shown over a wider dynamic range (e.g., a symmetric logarithmic scale) or with contours at a few sigma, so that the reader can assess the level of residuals at large radii.","section":"Figure 3"},{"comment":"Please clarify whether the sum is over the individual Gaussian components of the [O III] doublet and state how the flux-weighted shift is computed when both 4959 and 5007 lines are fitted simultaneously.","section":"Equation (2)"},{"comment":"The notation for upper and lower limits (e.g., '< 2.53' and '> 4.10' in the density column) should be explained in the table caption, as it is currently only described in the text.","section":"Table 2"}],"recommendation":"major_revision","confidential_remarks":"The paper is a good fit for MNRAS and the central analysis is sound in its current form, but the requested robustness tests are feasible with the existing data and would substantially increase confidence in the null result. The major concerns are specific to the completeness of the PSF subtraction; I do not see a need for new observations."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Quick take: this paper deserves a serious referee. It is a careful single-object study that makes a strong, if not airtight, case that the apparent kpc-scale high-velocity [OIII] in F13451+1232 is beam-smeared nuclear outflow rather than a galaxy-wide wind.\n\nWhat is actually new is not the method—PSF subtraction for IFU data has been done before—but the quantitative demonstration on a well-characterised QSO2/ULIRG with deep MUSE data. The cross-checks are the strong part. The Moffat FWHM fit to the nuclear-model flux distribution matches the stellar PSF within 1σ for [OIII] (0.74±0.02 vs 0.79±0.10 arcsec) and for Hα (0.43 vs 0.44 arcsec). That consistency makes it plausible that the nuclear-model light distribution really is just the seeing-smeared compact outflow. The free-fitting versus beam-smearing-corrected comparison is also a nice controlled demonstration of the bias, showing outflow radii and energetics inflated by orders of magnitude when beam smearing is ignored.\n\nThe soft spots are real but not fatal. The PSF-subtraction completeness rests on the assumption that the nuclear outflow is unresolved, circular, and well described by a single Moffat at all radii. If the true outflow is slightly extended (a few hundred pc) or asymmetric, that flux gets folded into the fitted PSF and subtracted. The stellar-PSF consistency is encouraging, but it does not rule out a small intrinsic extension. The fixed relative amplitudes of the two broad nuclear components are another a priori assumption: if the very broad component fades or changes velocity with radius, a genuinely extended, lower-velocity outflow could be absorbed into the scaled nuclear model. The residual maps are also shown at only ±0.04 of the peak, so faint large-scale wings would be hard to see. The cleanest independent check would be to compare the PSF-subtracted [OIII] residuals with the HST/ACS image at matched spatial scales; the authors cite Tadhunter et al. (2018) but do not make that comparison.\n\nNone of this undermines the central result. The paper is appropriately cautious, explicitly stating that low-velocity extended outflows cannot be ruled out, and the kinematic interpretation (merger gravitational motions vs outflows) is presented as a preference rather than a certainty.\n\nThis paper is for anyone reinterpreting ground-based IFU outflow measurements or working on outflow demographics. It deserves peer review, and the manuscript would be strengthened if the authors either added the HST comparison or justified its absence. I would accept it with that caveat.","headline":"A careful single-object beam-smearing analysis that makes a strong, if not airtight, case against galaxy-wide warm-ionised outflows in F13451+1232, with the PSF-subtraction completeness as the main residual uncertainty.","tokens_in":29041,"tokens_out":3460,"would_cite":true,"duration_ms":34791,"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":"Deep integral-field observations of the quasar F13451+1232 show that the apparent galaxy-wide high-velocity outflow is beam-smeared light from a compact 100-parsec nuclear outflow; once removed, the extended gas moves at modest velocities…","keywords":["AGN feedback","ionised outflows","beam smearing","atmospheric seeing","integral field spectroscopy","galaxy mergers","ultraluminous infrared galaxies","type-2 quasars"],"falsifier":"High-spatial-resolution spectroscopy that resolves the broad-wing [O III] emission at radii beyond about 1 kpc, for example space-based integral-field observations with a PSF narrower than 0.1 arcsecond, would directly show whether the extended high-velocity flux exists independently of the nuclear PSF; if it does, the null result is an artifact of oversubtraction. A more targeted check would allow the subtracted nuclear component a small intrinsic size of a few hundred parsecs and test whether the claimed residual extended emission disappears only for exactly zero intrinsic size.","tokens_in":2310,"feed_emoji":"🌪️","tokens_out":3776,"duration_ms":81264,"temperature":0.7,"pith_summary":"The paper claims that the fast, warm-ionised outflows once thought to extend across the galaxy F13451+1232 are an illusion caused by atmospheric seeing. Using deep integral-field spectroscopy, the authors model the bright compact nuclear outflow (radius about 69 pc) and show that its point-spread function, blurred by the atmosphere, can account for all the high-velocity (W80 > 500 km/s) emission out to radii beyond 3.5 arcseconds (about 7.4 kpc). After subtracting this beam-smeared component, the remaining extended gas shows modest kinematics (W80 mostly below 500 km/s) consistent with gravitational motions in a galaxy merger. They further show that ignoring beam smearing would inflate mass outflow rates by up to an order of magnitude and kinetic powers by one to two orders of magnitude. The result matters because previous ground-based claims of galaxy-wide AGN outflows may largely be seeing artifacts, and warm-ionised outflows may actually be confined to the central kiloparsecs.","feed_headline":"Fast quasar outflows stop at 100 parsecs, not galaxy-wide","feed_subtitle":"Seeing smeared a compact nuclear wind across the field; correcting for it cuts outflow power by up to 100x.","key_machinery":"The load-bearing object is the “nuclear model”: the two broad Gaussian components fitted to the [O III] line in a 0.4-arcsecond nuclear aperture, representing the compact outflow, whose spatial flux distribution is modelled by a two-dimensional Moffat profile. Because the peak flux of this component across the field is well described by a Moffat profile with FWHM consistent with the seeing disk measured from a star, the paper treats the entire extended broad-wing flux as PSF-smeared nuclear emission. It normalises the nuclear model, multiplies it by the Moffat profile in each spaxel, and subtracts this from the datacube before refitting the residual emission; the same procedure is applied to H$\\alpha$+[N II]. The Moffat PSF is the mechanism that converts an unresolved nuclear outflow into a quantitative, spaxel-by-spaxel correction across the whole field.","core_discovery":"Working on the type-2 quasar/ultraluminous infrared galaxy F13451+1232, the paper establishes that a compact (radius less than 100 pc), luminous nuclear outflow produces a high-velocity wing in [O III] whose flux distribution across the field matches the seeing point-spread function (FWHM 0.74 arcseconds at 5000 Å, consistent with the stellar PSF of 0.79 arcseconds). Fitting a fixed “nuclear model” plus additional Gaussian components to every spatial pixel removes the circular patch of W80 ~ 1500–2500 km/s emission previously attributed to a galaxy-wide outflow; only a region to the northwest remains, with W80 below 500 km/s. The corrected velocity maps show blue- and redshifted gas extending to about 12 kpc with flux-weighted velocity shifts below 250 km/s and W80 mostly below 500 km/s, which the paper interprets as merger-driven gravitational motions rather than AGN outflows. The paper also quantifies the correction: for apertures out to about 9 kpc, beam-smearing-corrected mass outflow rates are $\\dot{M}_{\\rm out} = 0.14$\\,$M_\\odot$\\,yr$^{-1}$ to $1.50$\\,$M_\\odot$\\,yr$^{-1}$ and kinetic-power coupling efficiencies are below $0.002$ per cent of $L_{\\rm bol}$, while the uncorrected values reach $7.4$\\,$M_\\odot$\\,yr$^{-1}$ and $0.06$ per cent. This is presented as direct evidence that failing to account for atmospheric seeing can turn a compact nuclear outflow into an apparent galaxy-wide one.","pith_inferences":["The same PSF-subtraction recipe could be applied to archival ground-based integral-field cubes of other quasars to test whether claimed galaxy-wide outflows survive; objects with a compact nuclear outflow and a well-measured PSF star are the easiest targets.","If this result generalises, AGN feedback models that require kiloparsec-scale warm-ionised outflows to quench star formation may need to rely on other gas phases, such as hot X-ray gas, or on the cumulative effect of multiple AGN episodes.","The paper’s upper-limit argument implies that a genuinely extended warm-ionised outflow carrying model-level kinetic power would need electron densities below roughly $10^{-4}$ cm$^{-3}$, a testable prediction for future low-surface-brightness spectroscopy.","At higher redshift the same physical outflow would appear even more beam-smeared, so redshift-dependent claims of outflow sizes from ground-based surveys could be systematically biased; matched-resolution space-based integral-field observations would calibrate the effect."],"forward_implications":["Outflow radii derived from ground-based integral-field data cannot be trusted unless beam smearing is modelled; for F13451+1232 the apparent high-velocity outflow radius drops from about 5.5 kpc to about 69 pc.","Failing to correct for seeing can overestimate mass outflow rates of extended gas by up to an order of magnitude and kinetic powers by one to two orders of magnitude, so some reported outflow coupling efficiencies may be too high.","The paper finds no galaxy-wide warm-ionised outflow in a system that galaxy-formation models use as a test case, supporting the view that warm-ionised AGN outflows are typically confined to the central kiloparsecs.","Circular patches of high velocity width in previously published velocity maps are likely seeing artifacts; in this object the beam-smeared component remains significant out to 3.5 arcseconds (7.4 kpc), more than eight times the HWHM of the seeing disk.","Because the kiloparsec-per-arcsecond scale increases with redshift, the beam-smearing bias becomes more severe for higher-redshift quasars observed from the ground."],"supporting_citations":[{"why":"Provides the HST [O III] imaging that establishes the compact 69-pc scale of the nuclear warm-ionised outflow and the arc-like structure used to interpret the extended emission.","marker":"Tadhunter et al. 2018"},{"why":"Defines the broad and very broad nuclear [O III] components that the paper adopts as the ‘nuclear model’ and supplies the bolometric luminosity and nuclear energetics used for comparison.","marker":"Rose et al. 2018"},{"why":"Precedents the argument that atmospheric seeing smears compact emission and inflates measured outflow radii, and reanalyses a claimed large-scale outflow as beam smearing.","marker":"Husemann et al. 2016"},{"why":"Shows the cold molecular outflow in F13451+1232 is confined to r < 120 pc and detects the kiloparsec-scale rotating molecular disk, supporting the compact-outflow interpretation.","marker":"Holden et al. 2024"},{"why":"Establishes the compact (r < 100 pc) neutral atomic outflow and the luminous young radio source, both of which anchor the multi-phase compact-outflow picture.","marker":"Morganti et al. 2013"},{"why":"Provides the prior large-scale kinematics, the star-cluster locations, and the H II-region identifications used to interpret the extended gas as merger gravitational motions.","marker":"Rodríguez Zaurín et al. 2007"},{"why":"Supplies the analytic Moffat profile that the paper fits to both the stellar PSF and the spatial flux distribution of the nuclear model.","marker":"Moffat 1969"},{"why":"Characterises the MUSE adaptive-optics point-spread function, justifying the use of a Moffat profile for the seeing-limited PSF at the relevant wavelengths.","marker":"Fusco et al. 2020"}],"fun_headline_variants":["Beam smearing makes quasar outflows appear galaxy-wide","Quasar outflows confined to 100 pc after seeing correction","Compact quasar outflow masquerades as galaxy-wide wind","Correcting seeing reveals quasar outflows only at 100 pc","No galaxy-wide outflows: just beam-smeared nuclear wind"],"cache_read_input_tokens":30848,"weakest_assumption_plain":"The argument assumes that the nuclear outflow’s light profile in the ground-based data is exactly point-like—identical to the stellar seeing PSF and describable by a single Moffat profile at all radii—so any residual broad-wing flux in a spaxel is attributed to the blurred compact outflow rather than to a genuinely extended outflow component.","fun_headline_variants_meta":{"raw":{"variants":["Beam smearing makes quasar outflows appear galaxy-wide","Quasar outflows confined to 100 pc after seeing correction","Compact quasar outflow masquerades as galaxy-wide wind","Correcting seeing reveals quasar outflows only at 100 pc","No galaxy-wide outflows: just beam-smeared nuclear wind"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000366,"raw_usage":{"total_tokens":2111,"prompt_tokens":1233,"completion_tokens":878,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":849,"completion_tokens_details":{"reasoning_tokens":801}},"tokens_in":849,"tokens_out":878,"duration_ms":24330,"temperature":1.0,"reasoning_tokens":801,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-12T12:01:30.099577+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"High-spatial-resolution spectroscopy that resolves the broad-wing [O III] emission at radii beyond about 1 kpc, for example space-based integral-field observations with a PSF narrower than 0.1 arcsecond, would directly show whether the extended high-velocity flux exists independently of the nuclear PSF; if it does, the null result is an artifact of oversubtraction. A more targeted check would allow the subtracted nuclear component a small intrinsic size of a few hundred parsecs and test whether the claimed residual extended emission disappears only for exactly zero intrinsic size.","supporting_citations":[],"review_version":1}