The role of grain size in active galactic nuclei torus dust models

González‐Martín, O.; Almeida, C. Ramos; Fritz, J.; Alonso‐Herrero, A.; Hönig, S. F.; Roche, P. F.; Esparza-Arredondo, Donají; García-Bernete, I.; García‐Burillo, S.; Osorio-Clavijo, Natalia; Ulises, Reyes-Amador,

doi:10.1051/0004-6361/202345858

Cited by 5 publications

(4 citation statements)

References 126 publications

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“…We also highlight the need to continue exploring the dust composition and grain sizes (e.g. Hönig & Kishimoto 2017;García-González et al 2017;Martínez-Paredes et al 2021;García-Bernete et al 2022;González-Martín et al 2023;Reyes-Amador et al 2023) and include the entire molecular content of ice mantles in torus models to better constrain key parameters such as the nuclear structure covering factor (i.e. nuclear obscuration).…”

Section: Discussionmentioning

confidence: 99%

“…has been previously studied (e.g. Sirocky et al 2008;Feltre et al 2012;Hatziminaoglou et al 2015;Martínez-Paredes et al 2020;González-Martín et al 2023). In Fig.…”

Section: Water Ices As Tracers Of the Innermost Obscurationmentioning

confidence: 99%

“…-of-the-art torus model have explored different dust distribution (smooth vs. clumpy;Fritz, Franceschini, & Hatziminaoglou 2006; Nenkova et al 2008a,b;Efstathiou & Rowan- Robinson 1995;Efstathiou et al 2022), dust geometries (torus vs. polar dust; e.g Hönig & Kishimoto 2017;Stalevski, Tristram, & Asmus 2019),. dust composition (silicates vs. graphites; e.g Hönig & Kishimoto 2017;González-Martín et al 2023(González-Martín et al 2023).…”

mentioning

confidence: 99%

“…dust composition (silicates vs. graphites; e.g Hönig & Kishimoto 2017;González-Martín et al 2023(González-Martín et al 2023).…”

mentioning

confidence: 99%

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The Galaxy Activity, Torus, and Outflow Survey (GATOS)

García‐Burillo

Alonso‐Herrero

Almeida

et al. 2021

A&A

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We present the first results of the Galaxy Activity, Torus, and Outflow Survey (GATOS), a project aimed at understanding the properties of the dusty molecular tori and their connection to the host galaxy in nearby Seyfert galaxies. Our project expands the range of active galactic nuclei (AGN) luminosities and Eddington ratios covered by previous surveys of Seyferts conducted by the Atacama Large Millimeter Array (ALMA), allowing us to study the gas feeding and feedback cycle in a combined sample of 19 Seyferts. We used ALMA to obtain new images of the emission of molecular gas and dust using the CO(3–2) and HCO+(4–3) lines as well as their underlying continuum emission at 870 μm with high spatial resolutions (0.1″ ∼ 7 − 13 pc) in the circumnuclear disks (CND) of ten nearby (D < 28 Mpc) Seyfert galaxies selected from an ultra-hard X-ray survey. Our new ALMA observations detect 870 μm continuum and CO line emission from spatially resolved disks located around the AGN in all the sources. The bulk of the 870 μm continuum flux can be accounted for by thermal emission from dust in the majority of the targets. For most of the sources, the disks show a preponderant orientation perpendicular to the AGN wind axes, as expected for dusty molecular tori. The median diameters and molecular gas masses of the tori are ∼42 pc and ∼6 × 105 M⊙, respectively. We also detected the emission of the 4–3 line of HCO+ in four GATOS targets. The order of magnitude differences found in the CO/HCO+ ratios within our combined sample point to a very different density radial stratification inside the dusty molecular tori of these Seyferts. We find a positive correlation between the line-of-sight gas column densities responsible for the absorption of X-rays and the molecular gas column densities derived from CO toward the AGN in our sources. Furthermore, the median values of both column densities are similar. This suggests that the neutral gas line-of-sight column densities of the dusty molecular tori imaged by ALMA significantly contribute to the obscuration of X-rays. The radial distributions of molecular gas in the CND of our combined sample show signs of nuclear-scale molecular gas deficits. We also detect molecular outflows in the sources that show the most extreme nuclear-scale gas deficits in our sample. These observations find for the first time supporting evidence that the imprint of AGN feedback is more extreme in higher luminosity and/or higher Eddington ratio Seyfert galaxies.

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Section: Discussionmentioning

confidence: 99%

“…has been previously studied (e.g. Sirocky et al 2008;Feltre et al 2012;Hatziminaoglou et al 2015;Martínez-Paredes et al 2020;González-Martín et al 2023). In Fig.…”

Section: Water Ices As Tracers Of the Innermost Obscurationmentioning

confidence: 99%

mentioning

confidence: 99%

“…dust composition (silicates vs. graphites; e.g Hönig & Kishimoto 2017;González-Martín et al 2023(González-Martín et al 2023).…”

mentioning

confidence: 99%

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The Galaxy Activity, Torus, and Outflow Survey (GATOS)

García‐Burillo

Alonso‐Herrero

Almeida

et al. 2021

A&A

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The Galaxy Activity, Torus, and Outflow Survey (GATOS)

García-Bernete,

Alonso-Herrero,

Rigopoulou

et al. 2023

A&A

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We use JWST/MIRI MRS spectroscopy of a sample of six local obscured type 1.9/2 active galactic nuclei (AGN) to compare their nuclear mid-IR absorption bands with the level of nuclear obscuration traced by X-rays. This study is the first to use subarcsecond angular resolution data of local obscured AGN to investigate the nuclear mid-IR absorption bands with a wide wavelength coverage (4.9–28.1 μm). All the nuclei show the 9.7 μm silicate band in absorption. We compare the strength of the 9.7 and 18 μm silicate features with torus model predictions. The observed silicate features are generally well explained by clumpy and smooth torus models. We report the detection of the 6 μm dirty water ice band (i.e., a mix of water and other molecules such as CO and CO2) at subarcsecond scales (∼0.26″ at 6 μm; inner ∼50 pc) in a sample of local AGN with different levels of nuclear obscuration in the range log NHX-Ray (cm−2)∼22 − 25. We find good correlation between the 6 μm water ice optical depths and NHX-Ray. This result indicates that the water ice absorption might be a reliable tracer of the nuclear intrinsic obscuration in AGN. The weak water ice absorption in less obscured AGN (log NHX-ray (cm−2)≲23.0 cm−2) might be related to the hotter dust temperature (> TsubH2O ∼ 110 K) expected to be reached in the outer layers of the torus due to their more inhomogeneous medium. Our results suggest it might be necessary to include the molecular content, such as H2O, aliphatic hydrocarbons (CH−), and more complex polycyclic aromatic hydrocarbon (PAH) molecules, in torus models to better constrain key parameters such as the torus covering factor (i.e., nuclear obscuration).

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X-ray polarisation in AGN circumnuclear media

Vander Meulen,

Camps,

Savić

et al. 2024

A&A

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Cold gas and dust reprocess the central X-ray emission of active galactic nuclei (AGN), producing characteristic spectro-polarimetric features in the X-ray band. The recent launch of IXPE allows for observations of this X-ray polarisation signal, which encodes unique information on the parsec-scale circumnuclear medium of obscured AGN. However, the models for interpreting these polarimetric data are under-explored and do not reach the same level of sophistication as the corresponding spectral models. We aim at closing the gap between the spectral and spectro-polarimetric modelling of AGN circumnuclear media in the X-ray band by providing the tools for simulating X-ray polarisation in complex geometries of cold gas alongside X-ray spectra. We lay out the framework for X-ray polarisation in 3D radiative transfer simulations and provide an implementation to the 3D radiative transfer code SKIRT, focussing on (de)polarisation due to scattering and fluorescent re-emission. As an application, we explored the spectro-polarimetric properties of a 2D toroidal reprocessor of cold gas, modelling the circumnuclear medium of AGN. For the 2D torus model, we find a complex behaviour of the polarisation angle with photon energy, which we interpret as a balance between the reprocessed photon flux originating from different sky regions, with a direct link to the torus geometry. We calculated a large grid of AGN torus models and demonstrated how spatially resolved X-ray polarisation maps could form a useful tool for interpreting the geometrical information that is encoded in IXPE observations. With this work, we release high-resolution AGN torus templates that simultaneously describe X-ray spectra and spectro-polarimetry for observational data fitting with XSPEC. The SKIRT code can now model X-ray polarisation simultaneously with X-ray spectra and provide synthetic spectro-polarimetric observations for complex 3D circumnuclear media, with all features of the established SKIRT framework available.

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The role of grain size in active galactic nuclei torus dust models

Cited by 5 publications

References 126 publications

The Galaxy Activity, Torus, and Outflow Survey (GATOS)

The Galaxy Activity, Torus, and Outflow Survey (GATOS)

The Galaxy Activity, Torus, and Outflow Survey (GATOS)

X-ray polarisation in AGN circumnuclear media

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