GATOS Survey: AGN Torus & Outflow Study

• GATOS Survey is a comprehensive, multiwavelength campaign that studies molecular tori, circumnuclear ISM, and outflows in Seyfert galaxies.
• It employs advanced instrumentation like ALMA, JWST/MIRI, and SOFIA to analyze AGN fueling, obscuration, and feedback across varying luminosities and environments.
• The survey delivers empirical metrics on torus dimensions, gas masses, and feedback-driven outflows, refining AGN unification and disk–wind models.

The Galaxy Activity, Torus, and Outflow Survey (GATOS) is a comprehensive, multiwavelength observational campaign designed to elucidate the physical characteristics, geometries, and evolutionary mechanisms of the dusty molecular tori, circumnuclear interstellar medium (ISM), and associated outflows in nearby Seyfert galaxies. By leveraging high spatial resolution data from ALMA, JWST/MIRI, SOFIA, and complementary facilities, GATOS systematically analyzes the interplay between AGN fueling, obscuration, and feedback across a broad range of AGN luminosities, Eddington ratios, and host galaxy environments.

1. Survey Motivation and Scientific Scope

The principal aim of GATOS is to provide a statistical and physical framework for understanding how gas fueling and AGN-driven feedback regulate the dense, dusty environments of low-redshift Seyferts. This approach builds on and extends previous surveys (e.g., NUGA), emphasizing:

• Characterization of the molecular tori structure (diameters, masses, orientations), their stratification, and relation to AGN unification.
• The spatial coupling between dusty tori, circumnuclear disks, ionized outflows, and multiphase feedback.
• Integration of molecular gas observables (CO(3–2), HCO$^+$(4–3)), dust continuum, and thermal/kinematic diagnostics with multiwavelength AGN properties (e.g., X-ray column densities, bolometric luminosities, Eddington ratios).
• Quantification of the impact of AGN-driven winds, jets, and radiation fields on the ISM, molecular depletion, polar dust emission, and the survival of small molecules such as PAHs.

GATOS selects targets to sample a dynamic range in AGN power and obscuration, providing a basis to test both static and dynamic (“disk+wind”) torus models and AGN feedback prescriptions.

2. Observational Methodologies

GATOS employs a suite of advanced instrumentation and data analysis techniques:

• ALMA Band 7 Imaging: High-fidelity mapping of CO(3–2), HCO$^+$(4–3), and 870–854 μm continuum at $\sim$0.1″ (7–13 pc) resolution. Observations combine extended and compact ALMA configurations to recover spatial scales from tens to hundreds of parsecs, enabling spatial separation of the unresolved AGN point source from the extended torus component (García-Burillo et al., 2021).
• JWST/MIRI Spectroscopy and Imaging: MIRI MRS provides sub-arcsecond IFU datacubes over 4.9–28.1 μm, allowing detailed decomposition of emission lines, PAH features, and continuum, while broadband MIRI imaging (F1000W–F2100W) at $\sim$75 pc (21 μm) resolution traces the extended dust distribution (García-Bernete et al., 2023, Lopez-Rodriguez et al., 25 Jul 2025).
• VLT/SINFONI IFU: Near-IR mapping of coronal and H$_2$ lines to trace ionized and molecular gas dynamics in synergy with ALMA (Alonso-Herrero et al., 2023).
• SOFIA FORCAST/HAWC+: Mid- to far-IR (20–214 μm) photometry and imaging, delivered at 3–20″ resolution (median 43 Mpc), complements the SED coverage and constrains dust temperature distribution (Fuller et al., 27 Nov 2024).
• Image Deconvolution: Tools such as the Kraken algorithm are applied to JWST/MIRIM and MRS imaging for PSF correction and resolution enhancement (FWHM reduction by factors $\sim$1.6–2.2), enabling detection of faint extended features in the nuclear regions (Leist et al., 2023).

Data reduction standardizes procedures (CASA, GILDAS, JWST pipeline) and includes morphological decomposition, Fourier-based kinematic modeling (kinemetry), and profile fitting for spectroscopic features.

3. Structural and Physical Properties of Tori and Circumnuclear ISM

The GATOS core results establish robust empirical metrics for molecular and dusty torus properties (Table 1):

Parameter	Typical Value (GATOS)	Method
Torus diameter	$\sim$42 pc	ALMA continuum fit
Torus gas mass	$\sim$6 × 10$^5$ M$_\odot$	ALMA CO, dust continuum
Torus orientation (vs. outflow)	$\perp$ to AGN wind	ALMA, NLR mapping
HCO$^+$(4–3)–CO(3–2) ratio	2.8–38 (order of mag.)	ALMA lines
Dust temperature (extended MIR)	$T_d=132^{+7}_{-7}$ K	JWST/MIRI SED modeling
Dust mass (75–450 pc regions)	$\sim$700 M$_\odot$	JWST/MIRI, blackbody fit

The continuum emission in most cases is dominated by thermal dust, with orientation typically perpendicular to the ionized outflow or wind axis—a configuration supporting equatorial obscuration in unified AGN models (García-Burillo et al., 2021, Alonso-Herrero et al., 2021, Fuller et al., 27 Nov 2024). Dense gas tracers such as HCO$^+$(4–3) reveal substantial density gradients within the tori.

A positive correlation is observed between CO-based column densities on 7–10 pc scales and X-ray absorption column densities toward the AGN, confirming the torus as a primary nuclear obscurer (García-Burillo et al., 2021). However, silicate absorption profiles and the presence/strength of the 6 μm water ice band demonstrate a wider molecular content (H$_2$O, hydrocarbons, PAHs) must be included in torus models to resolve differences in column density diagnostics (García-Bernete et al., 2023).

4. AGN Feedback, Outflows, and Dusty Winds

ALMA, JWST, and VLT observations in GATOS reveal that AGN feedback manifests as both molecular (cold and warm) and ionized outflows, with their impact modulated by AGN luminosity, Eddington ratio, and, in select cases, radio jet activity:

• Molecular Outflows: Observed as deficits in nuclear gas concentration (inner tens of parsecs) and kinematically distinct outflows traced by CO(3–2) and H$_2$ lines. Outflow rates of $\sim$40 M$_\odot$/yr in NGC 7172 characterize the mass fluxes involved (Alonso-Herrero et al., 2023). Outflow concentration indices decrease (by 1–2 dex) with rising AGN luminosity/Eddington ratio, consistent with more effective gas clearing via feedback (García-Burillo et al., 2021).
• Ionized Outflows: Spatially resolved maps of [Ne V], [Ar II], and [S IV] with JWST/MIRI reveal broad line profiles (W$_{80}$>$600 km/s) and misaligned velocity fields relative to the stellar disk in several galaxies. Radio jets are implicated as drivers or triggers, as outflow axes align with jet directions and disturbed regions are found perpendicular to them (Zhang et al., 15 Sep 2024).
• Extended MIR Emission and Dusty Winds: Contrary to prior interpretations, GATOS demonstrates that the polar MIR continuum emission (at 75–450 pc) is not spatially correlated with the ionized outflows or narrow emission lines expected from winds. The dust SEDs in these regions are well-fit by constant temperature ($\sim$132 K) modified blackbody emission, with mass and temperature uniformity across different AGN and no evidence for ongoing dusty mass loss. Instead, the dust is distributed in molecular clouds or heated by shocks, with the gravitational energy balance (using $\lambda_{\rm Edd}=0.044\,N_{\rm H,23}$$) indicating the sample is in the gravitationally bound, wind-suppressed regime (<a href="/papers/2507.19350" title="" rel="nofollow" data-turbo="false" class="assistant-link" x-data x-tooltip.raw="">Lopez-Rodriguez et al., 25 Jul 2025</a>, <a href="/papers/2404.16100" title="" rel="nofollow" data-turbo="false" class="assistant-link" x-data x-tooltip.raw="">Haidar et al., 24 Apr 2024</a>).</li> </ul> <h2 class='paper-heading' id='multiphase-gas-pah-survival-and-star-formation-diagnostics'>5. Multiphase Gas, PAH Survival, and Star Formation Diagnostics</h2> <p>JWST/MIRI high-resolution IFU observations uncover multiphase ISM structure and AGN feedback effects on molecular chemistry and star-formation tracers:</p> <ul> <li><strong>Warm Molecular Gas:</strong> Where millimeter CO is suppressed (e.g., due to AGN photoionization), JWST detects up to eight rotational H$$_2$$lines, revealing planar radial outflows and shock-excited gas at$$T>200$$K. Radial velocity profiles show acceleration (up to$$\sim$400 km/s) over $\sim$50 pc and subsequent deceleration as mass is loaded from the disk (Davies et al., 24 Jun 2024).
• PAH Diagnostics: Nuclear and outflow regions exhibit elevated 11.3/6.2 and 11.3/7.7 μm PAH ratios, indicating a higher fraction of neutral PAHs and selective destruction of the ionized PAH carriers (6.2, 7.7 μm) by AGN radiation and shocks. The PAH–H$_2$$diagram separates AGN- from star-formation-dominated regions, with the implication that PAH-based SFR indicators should be used with caution in AGN hosts (<a href="/papers/2409.05686" title="" rel="nofollow" data-turbo="false" class="assistant-link" x-data x-tooltip.raw="">García-Bernete et al., 9 Sep 2024</a>).</li> </ul> <h2 class='paper-heading' id='theoretical-context-modeling-and-machine-learning-applications'>6. Theoretical Context, Modeling, and Machine Learning Applications</h2> <p>GATOS has initiated several lines of theoretical and modeling developments to interpret its multiwavelength data:</p> <ul> <li><strong>Disk–Wind Models:</strong> Simulations (e.g., CAT3D-WIND) parameterize the relative contributions of clumpy equatorial tori and hollow-cone dusty winds. Model images convolved to observational resolutions reproduce observed morphologies, with polar wind prominence increasing at higher$$\lambda_{\rm Edd}$$or wind/disk cloud ratios (<a href="/papers/2107.00244" title="" rel="nofollow" data-turbo="false" class="assistant-link" x-data x-tooltip.raw="">Alonso-Herrero et al., 2021</a>).</li> <li><strong>Energy Balance and Dusty Wind Regimes:</strong> The critical energy balance for launching dusty winds is formalized as$$\lambda_{\rm Edd}=(2/3)\sigma_T N_H$, with most GATOS systems falling below this threshold—hence, wind signatures are generally suppressed in the MIR continuum (Lopez-Rodriguez et al., 25 Jul 2025).
• Black Hole Mass Estimation: A supervised machine learning pipeline, using simulated CO(3–2) cubes and convolutional neural networks trained on PVDs or moment maps, enables robust SMBH mass measurement with confidence intervals, providing improved precision over canonical scaling relations (Poitevineau et al., 27 Nov 2024).

7. Future Directions and Legacy

GATOS has set the stage for further studies by:

• Expanding samples to higher AGN luminosities and Eddington ratios to determine the persistence and universality of observed trends in torus clearing, gas phase stratification, and feedback efficiency.
• Extending JWST and ALMA mapping to direct 3D modeling of vertical disk structures, radial outflows, and disk warps, incorporating jet–ISM interactions and shock heating at sub-parsec to kiloparsec scales.
• Developing systematic comparisons with star-forming and non-AGN galaxies to identify AGN-unique perturbations in the circumnuclear ISM.
• Integrating SOFIA, Herschel, and future far-IR facilities to refine SED decompositions and dust mass/temperature constraints over broader wavelengths.

GATOS's approach—combining spatially resolved molecular, dust, and ionized gas probes with advanced modeling—has provided key constraints on the geometric, physical, and chemical structure of AGN environments and offers a scalable template for future surveys of AGN–ISM interaction and feedback.