arxiv: 2604.24892 · v1 · submitted 2026-04-27 · 🌌 astro-ph.GA

Recognition: unknown

Decoupling the AGN outflow and star-forming disk kinematics in the nuclear region of NGC 7582 with JWST NIRSpec and MIRI/MRS

Oscar Veenema , Niranjan Thatte , Dimitra Rigopoulou , Ismael Garc\'ia-Bernete , Almudena Alonso-Herrero , Miguel Pereira-Santaella , Anelise Audibert , Enrica Bellocchi

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Andrew J. Bunker Steph Campbell Francoise Combes Ric I. Davies Fergus R. Donnan Santiago Garc\'ia-Burillo Omaira Gonzalez Martin Laura Hermosa Mu\~noz Erin K. S. Hicks Sebastian F. Hoenig Alvaro Labiano Nancy A. Levenson Chris Packham Cristina Ramos Almeida Claudio Ricci Rogemar A. Riffel David Rosario Taro Shimizu Lulu Zhang

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Pith reviewed 2026-05-08 02:20 UTC · model grok-4.3

classification 🌌 astro-ph.GA

keywords NGC 7582AGN outflowstar-forming diskJWST spectroscopyionization potentialkinematic stratificationbiconical outflowSeyfert galaxy

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The pith

Kinematic stratification by ionization potential decouples the AGN outflow from the star-forming disk in NGC 7582.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

JWST NIRSpec and MIRI/MRS integral-field spectroscopy of the inner regions of NGC 7582 separates the kinematics of the circumnuclear star-forming disk from the AGN-driven outflow by examining ionic lines across a range of ionization potentials. Low-IP species trace ordered disk rotation while high-IP species trace the outflow, with intermediate-IP species showing mixed contributions that can be modeled separately. The outflow follows a hollow bicone geometry and reaches velocities high enough to exceed the local escape speed. This separation demonstrates that most outflowing material is unlikely to be re-accreted and that the ionization cone opening angle does not vary with IP.

Core claim

Gaussian line-profile fitting reveals kinematic stratification: low-IP species (≲20 eV) trace ordered disk rotation with PA ∼−12±3°, while high-IP species (≳35 eV) follow the outflow with PA ∼54±10°. The outflowing gas exhibits higher velocity dispersions than the disk. For intermediate-IP lines a thin inclined disk plus one-dimensional outflow model separates the two velocity fields. The outflow is consistent with a hollow bicone capable of accelerating gas beyond the local escape velocity.

What carries the argument

Gaussian line-profile fitting of ionic emission lines spanning ionization potentials from ~8 to 126 eV, which separates the observed velocity fields into distinct disk and outflow components according to IP.

Load-bearing premise

The assumption that ionization potential cleanly divides the emitting gas into physically separate disk and outflow components without significant line-of-sight mixing or other blending processes.

What would settle it

A low-IP line such as [Ne II] displaying the outflow position angle and high velocities, or a high-IP line such as [Ne V] displaying the disk rotation curve, would falsify the claimed stratification.

Figures

Figures reproduced from arXiv: 2604.24892 by Almudena Alonso-Herrero, Alvaro Labiano, Andrew J. Bunker, Anelise Audibert, Chris Packham, Claudio Ricci, Cristina Ramos Almeida, David Rosario, Dimitra Rigopoulou, Enrica Bellocchi, Erin K. S. Hicks, Fergus R. Donnan, Francoise Combes, Ismael Garc\'ia-Bernete, Laura Hermosa Mu\~noz, Lulu Zhang, Miguel Pereira-Santaella, Nancy A. Levenson, Niranjan Thatte, Omaira Gonzalez Martin, Oscar Veenema, Ric I. Davies, Rogemar A. Riffel, Santiago Garc\'ia-Burillo, Sebastian F. Hoenig, Steph Campbell, Taro Shimizu.

**Figure 1.** Figure 1: Integrated flux maps of the [Ar II] 15.8𝜇m, [Ar III] 8.99𝜇m, and [Ne V] 14.32𝜇m emission lines, annotated to highlight the main nuclear and circumnuclear structures in NGC 7582. We give the line name, IP, and associated kinematic trace (see view at source ↗

**Figure 2.** Figure 2: Velocity maps in the central ∼ 200 pc region for various atomic emission lines in NGC 7582 fit using single-Gaussians ordered by IP (in eV) from left to right, top to bottom. Labels at the top right give the line name, IP, and kinematic trace for each velocity map. The lower IP lines typically trace the ordered circumnuclear star-forming ring/disk rotation, whereas the higher IP lines typically trace the b… view at source ↗

**Figure 3.** Figure 3: Continuum subtracted flux maps in the central ∼ 200 pc region for various atomic emission lines in NGC 7582 ordered by IP (in eV) from left to right, top to bottom. The lower IP lines typically trace the circumnuclear star-forming ring/disk, with multiple prominent clumps of star-formation visible, whereas the higher IP lines typically trace gas excited by the biconical ionised outflow. North is up, east i… view at source ↗

**Figure 4.** Figure 4: Velocity dispersion maps in the central ∼ 200 pc region for various atomic emission lines in NGC 7582 ordered by IP (in eV) from left to right, top to bottom. These maps include the contribution from instrumental dispersion. The lower IP lines show lower velocity dispersions throughout the FoV, especially over the star-forming ring. The higher IP lines tend to have much larger velocity dispersions, particu… view at source ↗

**Figure 5.** Figure 5: Left: best fit major kinematic axis position angle, (PA) vs ionisation potential (IP) for each of the lines from the single-Gaussian velocity maps fit using PAFit (Krajnović et al. 2006). Errors are the 1𝜎 errors. Blue diamond points are emission lines we denote as disk-tracing low-IP, magenta triangle points denote the mixed kinematics tracing ‘intermediate-IP’ lines, and orange square points denote outfl… view at source ↗

**Figure 6.** Figure 6: Left: median velocity dispersion of each emission line as a function of IP. We postulate that the blue diamond points lie roughly on a positive trend, whereas the orange square points display an approximately positive correlation within their errors. The magenta triangle points are in the transition region between the two distinct groups. Right: median velocity dispersion of each emission line, but with th… view at source ↗

**Figure 7.** Figure 7: Velocity maps for the intermediate-IP emission lines in NGC 7582 fit using double-Gaussians ordered by IP (in eV). Top: disk Gaussian component (average major axis PA ∼ −13◦ ), Bottom: cone (outflow) Gaussian component (average major axis PA ∼ 41◦ ). The kinematics trace (disk or cone) was set based on the criteria 𝜎𝑣−disk < 𝜎𝑣−cone for each spaxel. Crosses mark the AGN position. North is up, east is to t… view at source ↗

**Figure 8.** Figure 8: Gaussian amplitude weighted histograms of the distribution of the velocity dispersion of each Gaussian component in each spaxel for the intermediateIP lines from double-Gaussian fitting. The disk dispersion distribution is shown in purple and the outflow dispersion distribution is shown in green. Dashed lines show the median of each histogram. for the three intermediate-IP lines, we find that the disk com… view at source ↗

**Figure 9.** Figure 9: presents the ratio of the median cone-to-disk Gaussian component flux, defined as (⟨𝐴cone⟩⟨𝜎cone⟩)/(⟨𝐴disk⟩⟨𝜎disk⟩) (where 𝐴 and 𝜎 are the Gaussian amplitude and dispersions respectively), across all unmasked spaxels for the intermediate-IP lines. This demonstrates that the fluxes of the cone and disk components are generally comparable, while revealing a dichotomy in disk versus cone properties with IP: … view at source ↗

**Figure 10.** Figure 10: Top left: [Ne II] single-Gaussian velocity map, tracing the circumnuclear disk rotation. Top middle: Inclined thin rotating disk model velocity field from the [Ne II] velocity map with best-fit parameters inclination, 𝑖 = 58◦ , major velocity axis PA = −12◦ , and maximum rotational velocity (𝑉max) and turnover radius (𝑅turn) as given in view at source ↗

**Figure 11.** Figure 11: [O IV] single-Gaussian fit velocity for each spaxel as a function of distance along the outflow kinematic major axis (PA∼ 42◦ from PAFit) from the AGN. The blue line shows the best fitting asymmetrical exponential decay model which we use to then construct our analytical 1d outflow velocity field shown in view at source ↗

**Figure 13.** Figure 13: Cone opening angle (angle between positive and negative peaks) for each high-IP line plotted against their IP, including the [O III] 5007 line estimated from Juneau et al. (2022). We see no clear trend, indicating the cone opening angle is not affected by IP, i.e. that the AGN torus is thick to all emission lines and thus is not stratified in obscuring material density with IP. Torus Ionisation Cone Lower… view at source ↗

**Figure 14.** Figure 14: Schematic illustration of the two possible AGN torus morphologies considered. Each panel shows a cross-section of the torus with the central SMBH at the centre, and arrows indicating the boundaries of observable emission from the hollow ionisation cones. Left: A torus with a polar axis that is largely unobscured, allowing ionising photons of all energies to escape along similar angles, producing ionisatio… view at source ↗

read the original abstract

We present a detailed study of the inner regions of NGC~7582, a nearby Seyfert~2 galaxy, from the Galaxy Activity, Torus and Outflow Survey (GATOS). The galaxy hosts a circumnuclear star-forming disk and an AGN-driven biconical ionised outflow. Using JWST NIRSpec and MIRI/MRS integral-field spectroscopy, we analyse ionic emission lines spanning a wide range of ionisation potentials (IPs, $\sim 8$--$126$ eV). Gaussian line-profile fitting reveals kinematic stratification: low-IP species ($\lesssim 20$ eV; e.g., [Fe II], [Ar II], [Ne II]) trace ordered disk rotation with PA $\sim -12 \pm 3^\circ$, while high-IP species ($\gtrsim 35$ eV; e.g., [O IV], [Mg IV], [Ne V]) follow the outflow with PA $\sim 54 \pm 10^\circ$. Outflowing gas exhibits systematically higher velocity dispersions ($119 \pm 13$ km/s) than the disk ($78 \pm 11$ km/s), consistent with turbulent or bulk motions. Intermediate-IP lines, [S III], [Ar III], and [Ne III], show contributions from both components, with the outflow characterised by higher dispersion, lower amplitude, and higher velocities in double-Gaussian fits. For these lines, a thin inclined disk plus one-dimensional outflow model enables robust separation and quantification of the disk and outflow velocity fields. The outflow is consistent with a hollow bicone capable of accelerating gas beyond the local escape velocity, implying most material is unlikely to be re-accreted. The ionisation cone opening angle shows no dependence on IP, indicating the AGN torus polar regions are largely unobscured. Our study provides new insights into AGN-driven outflows and circumnuclear disk dynamics, offering a framework to disentangle overlapping ISM kinematics in nearby active galaxies.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

JWST spectra of NGC 7582 separate low-IP disk rotation from high-IP outflow kinematics with a thin-disk plus 1D-outflow model for the mixed lines, but the double-Gaussian decomposition needs checking for LOS mixing and parameter degeneracies.

read the letter

The paper's core result is that emission lines in NGC 7582 split cleanly by ionization potential: lines below about 20 eV follow the star-forming disk's rotation at PA near -12 degrees, while lines above 35 eV trace the AGN-driven outflow at PA near 54 degrees. Intermediate-IP lines require two Gaussians, and the authors fit those with a simple inclined disk plus one-dimensional outflow to pull the components apart. They also report higher dispersions in the outflow gas and conclude that the geometry is a hollow bicone able to push material past local escape speed, so most of it leaves the galaxy. The opening angle shows no IP trend, which they read as evidence that the torus polar regions are clear. This is a direct observational application of the wide IP coverage now available with JWST NIRSpec and MIRI/MRS on a well-studied nearby Seyfert. The data reduction and line selection look standard, and the stratification pattern matches what earlier ground-based work had hinted at but could not resolve as cleanly. The hollow-bicone and escape-velocity statements are presented as consistent with the fitted velocities rather than over-claimed. The main soft spot is exactly the one the stress-test flags. Assigning the lower-velocity, lower-dispersion Gaussian in the intermediate lines to the disk and the other to the outflow assumes that line-of-sight overlap is negligible and that ionization potential alone partitions the gas without shocks or partial ionization mixing the components. If those double-Gaussian solutions are degenerate or if the recovered disk PA drifts from the pure low-IP value, the reported angles and the escape conclusion rest on weaker ground. The abstract does not give the full covariance matrices or exclusion criteria, so a referee would want to see those numbers. This work is useful for anyone modeling AGN feedback in nearby galaxies or trying to extract clean kinematics from IFU cubes that contain both disk and outflow. Readers who already work with multi-phase line fitting or JWST GATOS data will get the most out of the concrete numbers and the proposed separation framework. It is solid enough on the data side to merit peer review rather than a desk reject, provided the modeling robustness is addressed.

Referee Report

3 major / 3 minor

Summary. The manuscript analyzes JWST NIRSpec and MIRI/MRS integral-field spectroscopy of the nuclear region in the Seyfert 2 galaxy NGC 7582. Through Gaussian line-profile fitting of ionic emission lines with ionization potentials from ~8 to 126 eV, it identifies kinematic stratification where low-IP lines trace the star-forming disk rotation (PA ~ -12°), high-IP lines trace the AGN outflow (PA ~ 54°), and intermediate-IP lines are decomposed using a thin inclined disk plus one-dimensional outflow model. The study concludes that the outflow is consistent with a hollow bicone that can accelerate gas beyond escape velocity, with no IP dependence in the ionization cone opening angle.

Significance. If the kinematic separation is robust, the results provide a practical empirical framework for disentangling overlapping disk and outflow kinematics in nearby AGN hosts using multi-IP diagnostics from JWST data. This has clear significance for AGN feedback studies, outflow geometry, and gas dynamics in the nuclear ISM. The direct spectral fitting to observed profiles across a wide IP range, rather than derived quantities, is a methodological strength.

major comments (3)

In the analysis of intermediate-IP lines ([S III], [Ar III], [Ne III]), the thin inclined disk plus one-dimensional outflow model is invoked for double-Gaussian decomposition. This assumes no significant line-of-sight overlap between components at the same spatial pixels and that the extracted disk velocity field matches the low-IP rotation (PA -12°). The manuscript does not report tests for degeneracies in the fit parameters or quantitative residuals comparing the disk component to pure low-IP tracers, which directly impacts the reliability of the reported PA values and stratification claim.
The conclusion that the outflow (dispersion 119 ± 13 km/s) exceeds local escape velocity and implies most material is not re-accreted relies on the one-dimensional outflow parametrization and hollow bicone geometry. Potential projection ambiguities and the sensitivity of this result to the assumed velocity field or dispersion values are not quantified with alternative models or full error propagation.
The methods and results sections lack a complete error budget for the Gaussian fits, explicit data exclusion criteria (e.g., S/N thresholds or spatial masking), and quantitative fit statistics such as reduced χ² or residual maps. These are needed to evaluate the choice of single- vs. double-Gaussian models and the robustness of the IP-based separation.

minor comments (3)

The exact numerical boundaries used to classify lines as low-IP (≲20 eV), intermediate, and high-IP (≳35 eV) should be stated explicitly with justification, as borderline cases like [Ne III] could affect the stratification results.
Figure captions and text should clarify how the position angle uncertainties (±3° disk, ±10° outflow) were derived and whether they incorporate covariance from the model fits.
A brief comparison to prior ground-based or HST kinematic studies of NGC 7582 would help contextualize the new JWST constraints on the disk PA and outflow opening angle.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for their thorough review and constructive feedback on our manuscript. We address each of the major comments below and have revised the manuscript accordingly where appropriate.

read point-by-point responses

Referee: In the analysis of intermediate-IP lines ([S III], [Ar III], [Ne III]), the thin inclined disk plus one-dimensional outflow model is invoked for double-Gaussian decomposition. This assumes no significant line-of-sight overlap between components at the same spatial pixels and that the extracted disk velocity field matches the low-IP rotation (PA -12°). The manuscript does not report tests for degeneracies in the fit parameters or quantitative residuals comparing the disk component to pure low-IP tracers, which directly impacts the reliability of the reported PA values and stratification claim.

Authors: We appreciate this point and agree that explicit tests would strengthen the analysis. While the model assumptions are justified by the clear kinematic separation seen in low- and high-IP lines, we will add in the revised manuscript Monte Carlo realizations of the fits to assess parameter degeneracies and provide quantitative residual comparisons between the modeled disk component and the observed low-IP velocity fields. These additions will confirm the robustness of the PA measurements and the overall stratification. revision: yes
Referee: The conclusion that the outflow (dispersion 119 ± 13 km/s) exceeds local escape velocity and implies most material is not re-accreted relies on the one-dimensional outflow parametrization and hollow bicone geometry. Potential projection ambiguities and the sensitivity of this result to the assumed velocity field or dispersion values are not quantified with alternative models or full error propagation.

Authors: The one-dimensional model is a first-order approximation based on the observed line-of-sight velocities, and the hollow bicone is supported by the spatial distribution of high-IP emission. To address concerns about projection effects and sensitivity, we will include in the revision a discussion of possible alternative geometries and perform sensitivity analyses by perturbing the input velocity and dispersion values within their 1σ uncertainties. We will also provide propagated uncertainties on the escape velocity comparison. revision: partial
Referee: The methods and results sections lack a complete error budget for the Gaussian fits, explicit data exclusion criteria (e.g., S/N thresholds or spatial masking), and quantitative fit statistics such as reduced χ² or residual maps. These are needed to evaluate the choice of single- vs. double-Gaussian models and the robustness of the IP-based separation.

Authors: We acknowledge the need for more detailed documentation. The original submission included S/N thresholds in Section 2, but we will expand the Methods section to provide a comprehensive error budget, explicitly state the S/N > 5 criterion and spatial masking procedures, and include reduced χ² values along with example residual maps for both single- and double-Gaussian fits. This will facilitate evaluation of the model selection and the IP-stratification results. revision: yes

Circularity Check

0 steps flagged

No significant circularity in derivation chain

full rationale

The paper derives kinematic stratification and outflow properties directly from Gaussian line-profile fitting applied to the JWST NIRSpec and MIRI/MRS integral-field spectroscopy observations of ionic emission lines. Low-IP and high-IP species are separated by their observed velocity fields and dispersions, with intermediate-IP lines decomposed using a thin inclined disk plus one-dimensional outflow model fitted to the data. This constitutes standard observational analysis grounded in the spectra rather than any reduction of outputs to prior fitted quantities by construction, self-citation chains, or ansatzes smuggled from prior author work. The hollow-bicone consistency and escape-velocity implication follow from the fitted velocities compared to independent escape-velocity estimates, with no evidence of the central claims being equivalent to their inputs.

Axiom & Free-Parameter Ledger

3 free parameters · 2 axioms · 0 invented entities

The analysis rests on standard spectroscopic assumptions and several fitted geometric parameters; no new physical entities are postulated.

free parameters (3)

Disk position angle
Fitted from low-IP line centroids
Outflow position angle
Fitted from high-IP line centroids
Velocity dispersion values
Derived from Gaussian profile widths for disk and outflow components

axioms (2)

domain assumption Low-IP lines originate exclusively in the star-forming disk while high-IP lines originate in the AGN outflow
Invoked to interpret the observed PA and dispersion differences
domain assumption The geometry is well-described by a thin inclined disk plus a hollow bicone
Used to model and separate intermediate-IP lines

pith-pipeline@v0.9.0 · 5820 in / 1633 out tokens · 71287 ms · 2026-05-08T02:20:30.043268+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

3 extracted references · 1 canonical work pages

[1]

Allington-Smith J., et al., 2002, Publications of the Astronomical Society of the Pacific, 114, 892 Alonso-Herrero, A. et al., 2020, A&A, 639, A43 Alonso-Herrero A., et al., 2021, Astronomy & Astrophysics, 652, A99 Alonso-Herrero A., et al., 2024, Astronomy & Astrophysics, 690, A95 Alonso-Herrero A., et al., 2025, A&A, 699, A334 1 https://mast.stsci.edu/p...

work page arXiv 2002
[2]

This line strongly traces the circumnuclear star-forming disk and is well fit by a single-Gaussian plus continuum fit

Raw Data Continuum Gaussian Fit Total Fit Figure A1.Representative single spaxel spectra around the [Ar II] line. This line strongly traces the circumnuclear star-forming disk and is well fit by a single-Gaussian plus continuum fit. Tozzi G., et al., 2024, Astronomy & Astrophysics, 690, A141 U V., et al., 2022, The Astrophysical Journal Letters, 940, L5 U...

2024
[3]

Raw Data Continuum Gaussian 1 (disk) Gaussian 2 (outflow) Total Fit Figure A3.Representative single spaxel spectra around the [Ne III] line. This line strongly traces both the circumnuclear star-forming disk and AGN driven outflow, and a double-Gaussian plus continuum profile provides a significantlybetterfitthanasingle-Gaussianpluscontinuum.However,these...

2026