This is the second in a series of papers devoted to explore a set of six dusty models of active galactic nuclei (AGN) with available spectral energy distributions (SEDs). These models are the smooth torus by Fritz et al. (2006), the clumpy torus by Nenkova et al. (2008B), the clumpy torus by , the two phase torus by Siebenmorgen et al. (2015), the two phase torus by Stalevski et al. (2016), and the wind model by Hönig & Kishimoto (2017). The first paper explores discrimination among models and the parameter restriction using synthetic spectra (González-Martín et al. 2019A). Here we perform spectral fitting of a sample of 110 AGN drawn from the Swift/BAT survey with Spitzer /IRS spectroscopic data. The aim is to explore which is the model that describes better the data and the resulting parameters. The clumpy wind-disk model by Hönig & Kishimoto (2017) provides good fits for ∼50% of the sample, and the clumpy torus model by Nenkova et al. (2008B) is good at describing ∼30% of the objects. The wind-disk model by Hönig & Kishimoto (2017) is better for reproducing the mid-infrared spectra of Type-1 Seyferts (with 60% of the Type-1 Seyferts well reproduced by this model compared to the 10% well represented by the clumpy torus model by Nenkova et al. 2008B) while Type-2 Seyferts are equally fitted by both models (roughly 40% of the Type-2 Seyferts). Large residuals are found irrespective of the model used, indicating that the AGN dust continuum emission is more complex than predicted by the models or that the parameter space is not well sampled. We found that all the resulting parameters for our AGN sample are roughly constrained to 10-20% of the parameter space. Contrary to what is generally assumed, the derived outer radius of the torus is smaller (reaching up to a factor of ∼ 5 times smaller for 10 pc tori) for the smooth torus by Fritz et al. (2006) and the two phase torus by Stalevski et al. (2016) than the one derived from the clumpy torus by (Nenkova et al. 2008B). Covering factors and line-of-sight viewing angles strongly depend on the model used. The total dust mass is the most robust derived quantity, giving equivalent results for four of these models.

At distances from the active galaxy nucleus (AGN) where the ambient temperature falls below ∼1500-1800 K, dust is able to survive. It is thus possible to have a large dusty structure present which surrounds the AGN. This is the first of two papers aiming at comparing six dusty torus models with available SEDs, namely

In this paper, we present a multi-epoch analysis of NGC 1052, a prototypical low-luminisity active galactic nucleus, using XMM–Newton, Suzaku and NuSTAR observations taken from 2001 to 2017. This is the first time that results from NuSTAR observations have been reported for NGC 1052. Regarding technical aspects, we found a wavelength-dependent calibration issue between simultaneous XMM–Newton and NuSTAR spectra, characterized by a change in the photon index of $\rm { \Gamma _{NuSTAR}- \Gamma _{XMM-Newton}=0.17\pm 0.04}$. We use ancillary Chandra data to decontaminate the nuclear spectrum from circumnuclear contributors. We find that two baseline models can fit the broad (0.5–50 keV) X-ray spectrum of the source. One consists of a power-law-like continuum that is absorbed by a uniform absorber, and is reflected by neutral material, and a separate power-law component in the soft band. The second model consists of a clumpy absorber. The reflection component is still present, but not the soft-band power law. Instead, absorption by a warm absorber is necessary to fit the spectra. This is the first time that a reflection component has been established in this object, thanks to high-energy data from NuSTAR. This component is constant in flux and shape, supporting the idea that it is produced away from the central source (probably in the torus). We find flux, spectral slope and absorption variations on time-scales of months to years. We also find that a patchy absorber can explain the behaviour of this source better, as it is ∼200 times more likely than the uniform absorber and yields smaller intrinsic variations.

Dust close (∼few pc) to the accretion disk in active galactic nuclei (AGN) is key to understand many of their observational signatures and it is key to trace how the AGN is fed or even evolve along its duty cycle. With estimated sizes of less than 10 pc, as constrained by mid-infrared high angular resolution data, only the superb spatial resolution achieved by ALMA is able to actually image this dusty structure. However, the question regarding the conditions in which the dust at sub-milimeter (sub-mm) wavelengths where ALMA operates, arises. We study the detectability of the emission associated with the AGN dusty structure at sub-mm wavelengths using ALMA, in a theoretical and observational way. Theoretically, we use the Clumpy models from Nenkova et al. together with the mid-infrared to X-ray and the radio fundamental plane scaling relations. We find that it is more likely to detect bigger and denser dusty tori at the highest ALMA frequency (666 GHz/450 µm). We also find that with 1h at 353 GHz/850 µm and 10h at 666 GHz/450 µm we can detect, with a high detection limit, a 1 mJy torus (characteristic of bright AGN). This means, an object for which the unresolved SED at 12 µm has a flux ∼ 1 mJy. Observationally, we use four prototypical AGN: NGC 1052 (low-luminosity AGN), NGC 1068 (Type-2), NGC 3516 (Type 1.5), and IZw1 (QSO), with radio, sub-millimeter, and mid-IR data available. All the mid-infrared spectra are best fit with the smooth model reported by Fritz et al. A power law and a single, or a composition of, synchrotron component/s reproduce the cm radio wavelengths. We combined and extrapolated both fits to compare the extrapolation of both torus and jet contributors at sub-mm wavelengths with data at these wavelengths. Our observational results are consistent with our theoretical results. The most promising candidate to detect the torus is the QSO IZw1 (therefore, highly accreting sources in general), although it cannot be resolved due to the distance of this source. We suggest that to explore the detection of a torus at sub-mm wavelengths, it is necessary to perform an SED analysis including radio data, with particular attention to the angular resolution.

In order to understand the diversity of classes observed in active galactic nuclei (AGN), a geometrically and optically thick torus of gas and dust is required to obscure the central engine depending on the line of sight to the observer. We perform a simultaneous fitting of X-ray and mid-infrared (mid-IR) spectra to investigate if the same structure could produce both emissions and, if this the case, to obtain better constraints for the physical parameters of the torus. In this case we take advantage of the fact that both emissions show important signatures of obscuration. We used the nearby type-2 active nucleus IC 5063 as a test object. This object is ideal because of the wealth of archival data including some high resolution data. It also has a relatively high AGN luminosity that dominates at both X-ray and mid-IR frequencies. We use high spectral resolution NuSTAR and IRS/Spitzer spectra. The AGN dusty models used several physically motivated models. We found that the combination of the smooth torus models at mid-IR by Fritz et al. (2006) and at X-rays by Baloković et al. (2018), with the viewing and half-opening angles linked to the same value, is the best choice to fit the spectra at both wavelengths. This allows us to determine all the parameters of its torus. This result suggests that the structure producing the continuum emission at mid-IR and the reflection component at X-ray is the same. Therefore, we prove that this technique can be used to infer the physical properties of the torus, at least when AGN dust dominates the mid-IR emission and the reflection component is significant at X-rays.