Modeling the Strongest Silicate Emission Features of Local Type 1 AGNs

Abstract

We measure the 10 and 18µm silicate features in a sample of 67 local (z < 0.1) type 1 active galactic nuclei (AGN) with available Spitzer spectra dominated by non-stellar processes. We find that the 10µm silicate feature peaks at 10.3 +0.7 −0.9 µm with a strength (Si p = ln f p (spectrum)/f p (continuum)) of 0.11 +0.15 −0.36 , while the 18µm one peaks at 17.3 +0.4 −0.7 µm with a strength of 0.14 +0.06 −0.06 . We select from this sample sources with the strongest 10µm silicate strength (σ Si10µm > 0.28, 10 objects). We carry out a detailed modeling of the IRS/Spitzer spectra by comparing several models that assume different geometries and dust composition: a smooth torus model, two clumpy torus models, a two-phase medium torus model, and a disk+outflow clumpy model. We find that the silicate features are well modeled by the clumpy model of , and among all models those including outflows and complex dust composition are the best (Hoenig et al. 2017). We note that even in AGN-dominated galaxies it is usually necessary to add stellar contributions to reproduce the emission at the shortest wavelengths.

Modeling the unresolved NIR-MIR SEDs of local ($z<0.1$) QSOs

“…We note that in all cases, the parameters are consistent with the optical classification as type 1 AGN and that the dust mass is constrained between ∼ 10 4 − 10 5 M for most cases, while the covering factor ranges from ∼ 0.14 to 0.40 for the Disk+Wind H17 model until 0.95 for the Two-phase media S16 model. These covering factors are consistent with the ones obtained in previous works for type 1 AGNs (see e.g., Martínez-Paredes et al 2017;González-Martín et al 2019b;Martínez-Paredes et al 2020). However, it is important to note that the covering factor is model dependent, as showed by González-Martín et al (2019b).…”

“…Additionally, for PG 1440+356, the photometric point in the H band from HST/NICMOS is slightly above the best fitted model (Smooth F06), the Ks flux is an upper limit. In these two last cases, this is probably due to the limitation of the model in well fit simultaneously the NIR and MIR SEDs (see e.g., Martínez-Paredes et al 2020) and/or some marginal contamination from the host.…”

The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths

“…AGN silicate emission: In the case of some AGNs, two main MIR silicate emission features have been observed, one around ∼ 10-11 μm, and another around ∼ 17-18 μm, and there is no consensus to the exact wavelength at which each of these silicate emission features peaks (e.g. Hao et al 2005Hao et al , 2007Sturm et al 2005;Schweitzer et al 2008;Hatziminaoglou et al 2015;Martínez-Paredes et al 2020). Hereafter, we refer to the silicate features at shorter and longer wavelengths as the 11 μm and 18 μm features, respectively.…”

Radiation Hydrodynamics Models of Active Galactic Nuclei: Beyond the Central Parsec

“…This gives insight as to whether the diversity in small scale 'circum-sublimation-radius' simulation physics leads to a diversity in large-scale predictions, or whether the parameter space is degenerate and the sub-parsec physics can not be well constrained by super-parsec scale observations. This can also provide a theoretical justification for the wind+disk geometries required by radiation transfer simulations (Hönig & Kishimoto 2017;Stalevski et al 2017Stalevski et al , 2019González-Martín et al 2019a,b;Martínez-Paredes et al 2020). This approach can furthermore lead to an interpretation of the ambiguous results of observations, such as the conflicting explanations for apparently counter-rotating gas (García-Burillo et al 2016;Impellizzeri et al 2019).…”