{"id":"d9abd3b9-2d18-458f-8347-abbe856c91ef","arxiv_id":"2506.03888","paper_version":2,"verdict":"ACCEPT","confidence":"HIGH","novelty_score":3.0,"correctness_risk":"low","formal_verification":"none","parameter_count":0,"one_line_summary":"A comprehensive review concludes that AGN jets couple strongly to the host ISM on kpc scales, driving multi-phase outflows, turbulence, and mixed suppression and enhancement of star formation.","lead":"This review synthesizes three decades of theory and observations showing that relativistic jets from supermassive black holes can strongly disturb gas in their host galaxy's central kiloparsecs. It matters because it makes the case that jets are local feedback agents, shaping star formation and gas kinematics, and not just distant heaters of galaxy clusters.","discovery_kind":"review","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Quantitative jet-ISM coupling claims rest on simulations that do not resolve cooling lengths; the review self-flags this in §5.5, so the qualitative central claim stands but cited efficiencies should be treated as resolution-dependent.","rationale":"The reader's weakest_assumption identifies exactly the same load-bearing concern: the idealized, under-resolved simulations underpin the central quantitative claims. I agree that this is the most vulnerable point in the argument. However, the paper itself explicitly discloses this limitation in Section 5.5 (\"Higher resolution and longer simulations\") and elsewhere, and the review's headline claim is qualitative and also supported by independent observations of jet-driven outflows (e.g., IC 5063, B2 0258+35, 4C 31.04) and by non-relativistic simulations from other groups. The review does not overclaim convergence; it presents the simulations as state-of-the-art but unfinished. Therefore, while the quantitative efficiencies and phase-space details should be read as provisional, the central synthesis remains valid as a review-level statement. The verdict ACCEPT is appropriate, and my read does not change it.","tokens_in":61931,"tokens_out":6352,"duration_ms":68059,"concrete_test":"Run the single jet–cloud interaction setup of Mandal et al. (2024, §2) with adaptive mesh refinement resolving L_cool ≈ 0.1 pc in shocked cloud layers, matching the published jet power and cloud parameters. Compare the ablated cloud mass fraction and outflow kinetic energy within 500 pc at t = 1 Myr against the coarse-resolution run. A change exceeding ~50% would indicate that the confined-phase coupling efficiency is resolution-dependent; a change within ~20% would support the current quantitative claims.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The review's central claim—that jets couple strongly to the ISM during the confined phase and transfer ~10–20% of their kinetic energy to the gas—is primarily supported by kpc-scale simulations in which the cooling length at cloud surfaces (~0.014–1 pc, from Meenakshi et al. 2022, quoted in §5.5) is far below the grid resolution (typically ≳10 pc). Because ablation, cloud shredding, and the resulting multiphase structure are not converged, the phase-space distribution in Fig. 4 and the quantitative coupling efficiencies could be numerical artifacts. If resolved cooling shortens cloud destruction times or changes the partition of energy among phases, the emphasis on the confined phase as the dominant feedback channel would need adjustment. The review acknowledges this lacuna in §5.5, but the main text still presents these numbers and the multiphase outflow picture as established findings, not as resolution-dependent estimates.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This review synthesizes numerical simulation studies and observations of relativistic AGN jets interacting with the host galaxy ISM on kiloparsec scales. It traces the historical development from 1980s beam simulations to modern relativistic hydrodynamics with static fractal and turbulent ISM setups, defines three jet evolutionary phases (confined, breakout, classical), and summarizes simulated impacts on ISM kinematics, multiphase gas, turbulence, and star formation. It also compiles observational evidence in a table (Appendix B) and presents an analytical estimate of the confined-phase duration (Appendix A). The paper's central claim is that jets couple strongly to the kpc-scale ISM, particularly during the confined phase, transferring about 10-20% of their kinetic energy to the gas and driving multiphase outflows; this is supported by both simulations and observations.","tokens_in":62232,"tokens_out":10792,"duration_ms":91794,"significance":"If accepted, the review provides a useful and timely synthesis of a field that has moved from 'jets heat clusters' to 'jets also affect host galaxies.' Its main strengths are the explicit treatment of simulation technique limitations (Section 5.5), a self-contained analytical model of confinement timescales (Appendix A), and a carefully compiled observational catalogue (Table A1). It draws on independent simulation groups (Gaibler, Dugan, Tanner and Weaver, Talbot et al., Cielo et al.) in addition to the author's own series, and the qualitative conclusions are consistent with resolved observations such as IC 5063 and B2 0258+35. The review is honest about open questions, including unresolved cooling lengths, short runtimes, missing magnetic fields and cosmic rays. Because it is a review, the numerical efficiency figures it quotes are not new results; the main risk is that readers may over-interpret resolution-dependent numbers as robust.","major_comments":[{"comment":"The quoted kinetic-energy coupling efficiencies (10-20%) and the multiphase phase-space classification are load-bearing for the paper's emphasis on the confined phase, but the simulations from which they are drawn do not resolve the cooling lengths (0.014-1 pc) quoted in Section 5.5. The main text should explicitly caveat these numbers as resolution-dependent at the point of first use (e.g., 'in the currently achievable resolution regime'), with a cross-reference to Section 5.5, rather than presenting them as established values.","section":"Section 3.1 and Section 3.3.1 (Figure 4)"},{"comment":"The numerical coefficient 1.75e3 km/s does not follow from Equation (A4) with the stated fiducial values unless the ambient density includes a mean molecular weight mu approximately 0.6. The text never defines whether na is hydrogen number density or total gas number density, nor the assumed mu. Please state the assumed mu (or correct the coefficient); this affects the quantitative values in Figure A1, although the qualitative scaling is unchanged.","section":"Appendix A, Equation (A5)"}],"minor_comments":[{"comment":"The text refers to 'the phase-space distributions of Fig. 3' but the quantity being described is shown in Figure 4; please correct the cross-reference.","section":"Section 3.3.1 (Hot tenuous outflow)"},{"comment":"Reference [486] appears between [206] and [208] with no [207], and the citation to 'shock precursors [486]' in Section 3.3.1 uses this out-of-sequence number; a global renumbering pass would be helpful.","section":"Reference list and citation [486]"},{"comment":"The source name is given as 'PKS 2152-69' in the main text and Table A1 but as 'PKS B2152-699' in reference [221]; please unify the name.","section":"Appendix B, row 41"},{"comment":"The caption contains the typo 'Several distinct phases have been be identified'; please remove the repeated 'be'.","section":"Figure 4 caption"},{"comment":"The Received/Accepted dates and copyright year (copyright 2024) are inconsistent with the 2025 submission/acceptance dates; please check issue metadata at production.","section":"Header metadata"}],"recommendation":"minor_revision","confidential_remarks":"The manuscript appears to be a commissioned-style review for Galaxies; the header contains template placeholders (Academic Editor, blank publication date) and a copyright-year mismatch that should be fixed at production. The author's reliance on their own simulation series is balanced by citations to independent groups and observations, so I do not see a novelty-disclosure concern. The paper fits the journal's scope. The stress-test concern about unresolved cooling lengths is already partially addressed in Section 5.5; the requested change is to make that caveat visible where the efficiencies are first quoted."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"The thing to know: this is a review, not a new result, but it's a good one. It makes the case that relativistic jets act as local feedback agents in the host ISM on kpc scales, beyond their well-known role as cluster-scale heaters, and the case holds.\n\nWhat it does well: the historical sweep from early jet-beam simulations through to current relativistic jet-ISM work is clear and well organized. The three-phase picture (confined, breakout, classical) gives a useful framework. The discussion of multiphase outflows, turbulence, and star formation effects is grounded in the cited literature, including independent groups (Gaibler, Tanner and Weaver, Talbot et al.), so the core claim doesn't rest solely on the author's own simulations. Appendix A's confinement-time estimate is a modest but clean extension of standard jet-head advance scalings with a volume-filling-weighted average, and it matches the simulation results quoted. The observational table in Appendix B is a genuinely handy resource.\n\nSoft spots: the paper is honest about its biggest caveat, and it's a real one. Section 5.5 states that cooling lengths at cloud surfaces are ~0.014-1 pc, well below the grid resolution (typically >10 pc). That means the simulated ablation, cloud shredding, and multiphase structure are not converged. The main text still quotes ~10-20% kinetic energy coupling and shows the phase-space distribution (Fig. 4) as established findings; those numbers should be labeled as resolution-dependent. The caveat is in the paper, but it's separated from the numbers. That's the one substantive thing I'd want fixed. Also, the review leans on the author's own series, though not problematically, and there are minor production artifacts (template formatting, a reference-numbering jump) that don't affect content.\n\nFor whom: a graduate student or a researcher entering this area will get a lot out of it; someone working in jet-ISM interaction will find a useful summary and a good reference list. It deserves a serious referee. I'd recommend accepting it with a revision that moves the resolution caveat closer to the figures and tables that depend on it.","headline":"A competent, honest review that consolidates the case for jets as kpc-scale ISM feedback agents; the central claim holds, but the quantitative coupling efficiencies should be labeled resolution-dependent.","tokens_in":62622,"tokens_out":2270,"would_cite":true,"duration_ms":22354,"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":"Relativistic jets from active galactic nuclei couple strongly to their host galaxy's gas on kiloparsec scales, driving multi-phase outflows and altering star formation.","keywords":["AGN feedback","relativistic jets","jet-ISM interaction","multi-phase outflows","interstellar medium","galactic turbulence","star formation feedback","numerical simulations"],"falsifier":"Run the same jet-and-galaxy setup at resolutions that resolve the 0.014–1 pc cooling lengths at cloud surfaces and compare outflow masses, velocities, and multi-phase structure; if the resolved runs show substantially weaker ablation or different cloud shredding than the existing simulations, the central claim about strong jet–ISM coupling would need to be scaled back.","tokens_in":61730,"feed_emoji":"🌌","tokens_out":6820,"duration_ms":60521,"temperature":0.7,"pith_summary":"This review tries to establish that relativistic jets from active galactic nuclei couple strongly to the interstellar medium of their host galaxies on kiloparsec scales, in contrast to the older view that jets matter mainly for heating cluster-scale gas. The author traces three decades of numerical simulations, from early two-dimensional beam models to relativistic hydrodynamic runs with fractal, turbulent gas discs, and sets them beside spatially resolved observations of multi-phase gas. The synthesis points to a confinement phase, when the jet is trapped inside dense clumpy gas, as the stage of maximal energy transfer: jets can deposit roughly ten to twenty percent of their flux as kinetic energy in the ISM, raise gas turbulence by an order of magnitude, and drive fast outflows in several gas phases. The review concludes that jets therefore belong in the same feedback category as quasar winds, with consequences for how star formation and black hole growth are regulated.","feed_headline":"Jets reshape their host galaxy's gas, not just the cluster halo","feed_subtitle":"A review of simulations and observations shows jets drive multi-phase outflows and stir star-forming gas on kpc scales.","key_machinery":"The organising mechanism is the three-phase life cycle of a jet in an inhomogeneous medium: the confined phase, the breakout phase, and the classical phase. During the confined phase, dense clouds act as obstacles that stall the jet head, and the jet plasma percolates through gaps in a 'flood-channel' pattern; the stalled beam's energy is redistributed into an overpressured bubble bounded by a forward shock. The review also carries an analytic estimate of the confinement timescale, obtained by equating the relativistic momentum flux of the jet to the ram pressure of clouds and writing the travel time through a scale height in terms of the jet power, cloud density, and volume filling factor. This machinery selects which jets stay trapped long enough to couple strongly with the ISM, and it is supplemented by a turbulence-regulated star formation prescription that converts local density, Mach number, and virial parameter into a star formation rate.","core_discovery":"On the paper's own terms, the discovery being argued for is that a relativistic jet acts as a direct feedback agent on its host ISM rather than only as a heater of large-scale environments. During the confined phase before breakout, the jet beam is diverted through low-density channels between clouds, while its backflow inflates a quasi-spherical, pressurized bubble that sweeps the surrounding gas. This bubble ablates clouds, accelerates warm dense gas to hundreds of kilometres per second, and excites a hot tenuous outflow, producing the multi-phase outflow structure seen in observations of sources such as IC 5063 and B2 0258+35. A further claim is that jets can affect a volume of the ISM much larger than their apparent radio width, so the radio beam underestimates the footprint of feedback. The long-term outcome is usually not a blowout: only a small fraction of the ISM escapes the galaxy, and most uplifted gas falls back in a fountain, while star formation is modified both negatively and positively depending on local conditions.","pith_inferences":["If the confined-phase coupling is as strong as this review argues, the traditional split between quasar-mode and radio-mode feedback needs revision: low-power, radio-quiet jets may contribute as much as winds to establishment-mode feedback in gas-rich hosts.","Because the simulated cooling lengths at cloud surfaces are one to two orders of magnitude below current resolution, converged simulations will likely revise the quoted 10–20% coupling efficiency; targeted observations of outflow energetics could provide the empirical anchor for that calibration.","The predicted enhancement of velocity dispersion perpendicular to the jet axis is a clean, testable diagnostic: existing IFU surveys already show it, and a systematic comparison between jet inclination and measured line widths would confirm whether the flood-channel mechanism operates as modelled."],"forward_implications":["During the confined phase, jets transfer on the order of 10–20% of their energy flux into the kinetic energy of ISM gas, making this phase the main channel of kpc-scale jet feedback.","A jet can stir a volume of the gas much larger than its radio beam, so narrow jets in observed galaxies do not imply weak feedback.","The efficiency of coupling is set by four parameters: jet power, orientation relative to the gas disk, volume filling factor of dense gas, and cloud density; low-power jets can remain confined for many megayears.","Only about ten percent of the ISM escapes the galaxy in such simulations; the rest returns in a galactic fountain, so jet feedback predominantly redistributes gas rather than ejecting it.","Applying turbulence-regulated star formation models, the jet mildly suppresses global star formation at onset while creating local, shock-compressed regions of enhanced star formation until breakout."],"supporting_citations":[{"why":"Introduced the fractal two-phase ISM setup and the three evolutionary phases (confined, breakout, classical) that structure the review's argument.","marker":"[52]"},{"why":"First relativistic jet simulations in a static fractal ISM; established the flood-channel confinement picture.","marker":"[171]"},{"why":"Parameter study across jet power, cloud density, and filling factor that quantified energy transfer and the mechanical advantage of jets.","marker":"[190]"},{"why":"Added a gravitational potential and hydrostatic atmosphere to jet feedback simulations; produced the escape-fraction result underpinning the galactic fountain conclusion.","marker":"[178]"},{"why":"Benchmark relativistic jet simulations in a gas disk; supplied the turbulent velocity dispersion and multi-phase phase-space results central to the review.","marker":"[172]"},{"why":"Simulation of jet–ISM interaction in IC 5063; provides the direct simulation-observation comparison for ionized gas kinematics.","marker":"[198]"},{"why":"ALMA detection of a fast molecular outflow in IC 5063; a key observational anchor for jet-driven cold gas outflows.","marker":"[210]"},{"why":"Observational case of cold gas removal from the centre of a galaxy by a low-luminosity jet; supports the kpc-scale clearing claim.","marker":"[214]"},{"why":"Applies turbulence-regulated star formation theory to jet feedback simulations; grounds the review's star formation impact claims.","marker":"[201]"}],"fun_headline_variants":["Jets inflate bubbles that sweep and shake galaxy gas","Jets affect more gas than their radio beam shows","Jets drive fountains, not blowouts, in galaxy centers","Jets stir host ISM, not just cluster halos"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that idealized numerical setups—static fractal gas distributions, pressure-equilibrated clouds, and single-fluid thermodynamics—capture the essential physics of how real jets couple to the clumpy interstellar medium, even though cloud-surface cooling is not resolved.","fun_headline_variants_meta":{"raw":{"variants":["Jets inflate bubbles that sweep and shake galaxy gas","Jets affect more gas than their radio beam shows","Jets drive fountains, not blowouts, in galaxy centers","Jets stir host ISM, not just cluster halos"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000353,"raw_usage":{"total_tokens":1919,"prompt_tokens":943,"completion_tokens":976,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":559,"completion_tokens_details":{"reasoning_tokens":907}},"tokens_in":559,"tokens_out":976,"duration_ms":8637,"temperature":1.0,"reasoning_tokens":907,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-07T10:52:21.731100+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Run the same jet-and-galaxy setup at resolutions that resolve the 0.014–1 pc cooling lengths at cloud surfaces and compare outflow masses, velocities, and multi-phase structure; if the resolved runs show substantially weaker ablation or different cloud shredding than the existing simulations, the central claim about strong jet–ISM coupling would need to be scaled back.","supporting_citations":[],"review_version":1}