The Experts below are selected from a list of 123504 Experts worldwide ranked by ideXlab platform
Moshe Elitzur - One of the best experts on this subject based on the ideXlab platform.
-
on the difference of Torus geometry between hidden and non hidden broad line active galactic nuclei
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Kohei Ichikawa, Yoshihiro Ueda, A Alonsoherrero, C Packham, Cristina Ramos Almeida, Andres Asensio Ramos, O Gonzalezmartin, Enrique Lopezrodriguez, T Diazsantos, Moshe ElitzurAbstract:We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy Torus models. We compiled high spatial resolution ($\sim 0.3$--$0.7$ arcsec) mid-IR $N$-band spectroscopy, $Q$-band imaging and nuclear near- and mid-IR photometry from the literature. Combining these nuclear near- and mid-IR observations, far-IR photometry and clumpy Torus models, enables us to put constraints on the Torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties; type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the Torus model parameters gives us the first quantitative Torus geometrical view for each subgroup. We find that NHBLR AGN have smaller Torus opening angles and larger covering factors than those of HBLR AGN. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small Torus opening angle and (b) the increased Torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGN.
-
dusty structure around type i active galactic nuclei clumpy Torus narrow line region and near nucleus hot dust
The Astrophysical Journal, 2009Co-Authors: Hagai Netzer, Moshe ElitzurAbstract:We fitted Spitzer/IRS approx 2-35 mum spectra of 26 luminous quasi-stellar objects in an attempt to define the main emission components. Our model has three major components: a clumpy Torus, dusty narrow-line region (NLR) clouds, and a blackbody-like dust. The models utilize the clumpy Torus of Nenkova et al. and are the first to allow its consistent check in type-I active galactic nuclei (AGNs). Single Torus models and combined Torus-NLR models fail to fit the spectra of most sources, but three-component models adequately fit the spectra of all sources. We present Torus inclination, cloud distribution, covering factor, and Torus mass for all sources and compare them with bolometric luminosity, black hole mass, and accretion rate. The Torus mass is found to be correlated with the bolometric luminosity of the sources. Torus-covering factor may also be (anti-)correlated, if some possibly anomalous points are omitted. We find that a substantial amount of the approx2-7 mum radiation originates from a hot dust component, which is likely situated in the innermost part of the Torus. The luminosity radiated by this component and its covering factor are comparable to those of the Torus. We quantify the emission by the NLR clouds and estimate their distancemore » from the center. The distances are approx700 times larger than the dust sublimation radius, and the NLR-covering factor is about 0.07. The total covering factor by all components is in good agreement with the known AGN type-I:type-II ratio.« less
-
dusty structure around type i active galactic nuclei clumpy Torus narrow line region and near nucleus hot dust
arXiv: Cosmology and Nongalactic Astrophysics, 2009Co-Authors: Rivay Mor, Hagai Netzer, Moshe ElitzurAbstract:We fitted Spitzer/IRS ~2-35 um spectra of 26 luminous QSOs in attempt to define the main emission components. Our model has three major components: a clumpy Torus, dusty narrow line region (NLR) clouds and a blackbody-like dust. The models utilize the clumpy Torus of Nenkova et al. (2008) and are the first to allow its consistent check in type-I AGNs. Single Torus models and combined Torus-NLR models fail to fit the spectra of most sources but three component models adequately fit the spectra of all sources. We present Torus inclination, cloud distribution, covering factor and Torus mass for all sources and compare them with bolometric luminosity, black hole mass and accretion rate. The Torus covering factor and mass are found to be correlated with the bolometric luminosity of the sources. We find that a substantial amount of the ~2-7 um radiation originates from a hot dust component, which likely situated in the innermost part of the Torus. The luminosity radiated by this component and its covering factor are comparable to those of the Torus. We quantify the emission by the NLR clouds and estimate their distance from the center. The distances are ~700 times larger than the dust sublimation radius and the NLR covering factor is about 0.07. The total covering factor by all components is in good agreement with the known AGN type-I:type-II ratio.
Yoshihiro Ueda - One of the best experts on this subject based on the ideXlab platform.
-
systematic study of agn clumpy tori with broadband x ray spectroscopy updated unified picture of agn structure
The Astrophysical Journal, 2021Co-Authors: Shoji Ogawa, A Tanimoto, Yoshihiro Ueda, S YamadaAbstract:We present the results of a systematic, broadband X-ray spectral analysis of nearby active galactic nuclei (AGNs) with the X-ray clumpy Torus model (XCLUMPY; Tanimoto et al. 2019). By adding 16 AGNs newly analyzed in this paper, we study total 28 AGNs including unabsorbed and absorbed AGNs taken from Ichikawa et al. (2015) and Garc\'ia-Bernete et al. (2019). This is the largest sample whose X-ray and infrared spectra are analyzed by the clumpy Torus models XCLUMPY and CLUMPY (Nenkova et al. 2008), respectively. The relation between the Eddington ratio and the Torus covering factor determined from the X-ray Torus parameters of each object follows the trend found by Ricci et al. (2017) based on a statistical analysis. We confirm the results by Tanimoto et al. (2020) that (1) the Torus angular widths determined by the infrared data are larger than those by the X-ray data and that (2) the ratios of the hydrogen column density to V-band extinction ($N_{\rm H}/A_{\rm V}$) along the line of sight in obscured AGNs are similar to the Galactic value on average. Unobscured AGNs show apparently smaller line-of-sight $N_{\rm H}/A_{\rm V}$ ratios than the Galactic one. Our findings can be well explained by an updated unified picture of AGN structure including a dusty Torus, dusty polar outflows, and dust-free gas, where the inclination determines the X-ray and optical classifications and observed Torus properties in the X-ray and infrared bands.
-
Torus constraints in anepd cxo245 a compton thick agn with double peaked narrow lines
The Astrophysical Journal, 2019Co-Authors: T Miyaji, A Tanimoto, Yoshihiro Ueda, Martin Herreraendoqui, M Krumpe, Masaki Hanzawa, Ayano Shogaki, Shuji Matsuura, T Ishigaki, Laia BarrufetAbstract:We report on the Torus constraints of the Compton-thick active galactic nucleus (AGN) with double-peaked optical narrow-line region emission lines, ANEPD-CXO245, at z = 0.449 in the AKARI NEP Deep Field. The unique infrared data on this field, including those from the nine-band photometry over 2–24 μm with the AKARI Infrared Camera, and the X-ray spectrum from Chandra allow us to constrain Torus parameters such as the Torus optical depth, X-ray absorbing column, Torus angular width (σ), and viewing angle (i). We analyze the X-ray spectrum as well as the UV–optical–infrared spectral energy distribution (UOI-SED) with clumpy Torus models in X-ray (XCLUMPY) and infrared (CLUMPY), respectively. From our current data, the constraints on σ–i from both X-rays and UOI show that the line of sight crosses the Torus as expected for a type 2 AGN. We obtain a small X-ray scattering fraction (<0.1%), which suggests narrow Torus openings, giving preference to the bipolar outflow picture of the double-peaked profile. Comparing the optical depth of the Torus from the UOI-SED and the absorbing column density NH from the X-ray spectrum, we find that the gas-to-dust ratio is <4 times larger than the Galactic value.
-
erratum xclumpy x ray spectral model from clumpy Torus and its application to the circinus galaxy 2019 apj 877 95
The Astrophysical Journal, 2019Co-Authors: A Tanimoto, Yoshihiro Ueda, Hirokazu Odaka, Toshihiro Kawaguchi, Y Fukazawa, T KawamuroAbstract:We construct an X-ray spectral model from the clumpy Torus in an active galactic nucleus (AGN), designated as "XCLUMPY", utilizing the Monte Carlo simulation for Astrophysics and Cosmology framework (MONACO: Odaka et al. 2011, 2016). The adopted geometry of the Torus is the same as that in Nenkova et al. (2008), who assume a power law distribution of clumps in the radial direction and a normal distribution in the elevation direction. We investigate the dependence of the X-ray continuum and Fe K$\alpha$ fluorescence line profile on the Torus parameters. Our model is compared with other Torus models: MYTorus model (Murphy & Yaqoob 2009), Ikeda model (Ikeda et al. 2009), and CTorus model (Liu & Li 2014). As an example, we also present the results applied to the broadband X-ray spectra of the Circinus galaxy observed with XMM-Newton, Suzaku, and NuSTAR. Our model can well reproduce the data, yielding a hydrogen column density along the equatorial plane $N_{\mathrm{H}}^{\mathrm{Equ}} = 9.08_{-0.08}^{+0.14} \times 10^{24}$ cm$^{-2}$, a Torus angular width $\sigma = 14.7_{-0.39}^{+0.44}$ degree, and a 2--10 keV luminosity $\log L_{2-10}/\mathrm{erg \ s^{-1}} = 42.8$. These results are discussed in comparison with the observations in other wavelengths.
-
Torus constraints in anepd cxo245 a compton thick agn with double peaked narrow lines
arXiv: Astrophysics of Galaxies, 2019Co-Authors: T Miyaji, A Tanimoto, Yoshihiro Ueda, Martin Herreraendoqui, M Krumpe, Masaki Hanzawa, Ayano Shogaki, Shuji Matsuura, T Ishigaki, Laia BarrufetAbstract:We report on the Torus constraints of the Compton-thick AGN with double-peaked optical narrow line region (NLR) emission lines, ANEPD-CXO245, at z=0.449 in the AKARI NEP Deep Field. The unique infrared data on this field, including those from the nine-band photometry over 2-24 $\mu$m with the AKARI Infrared Camera (IRC), and the X-ray spectrum from Chandra allow us to constrain Torus parameters such as the Torus optical depth, X-ray absorbing column, Torus angular width ($\sigma$) and viewing angle ($i$). We analyze the X-ray spectrum as well as the UV-optical-infrared spectral energy distribution (UOI-SED) with clumpy Torus models in X-ray (XCLUMPY; Tanimoto et al. 2019) and infrared (CLUMPY; Nenkova et al. 2008) respectively. From our current data, the constraints on $\sigma$--$i$ from both X-rays and UOI show that the line of sight crosses the Torus as expected for a type 2 AGN. We obtain a small X-ray scattering fraction (<0.1%), which suggests narrow Torus openings, giving preference to the bi-polar outflow picture of the double-peaked profile. Comparing the optical depth of the Torus from the UOI-SED and the absorbing column density $N_{\rm H}$ from the X-ray spectrum, we find that the gas-to-dust ratio is $\gtrsim 4$ times larger than the Galactic value.
-
on the difference of Torus geometry between hidden and non hidden broad line active galactic nuclei
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Kohei Ichikawa, Yoshihiro Ueda, A Alonsoherrero, C Packham, Cristina Ramos Almeida, Andres Asensio Ramos, O Gonzalezmartin, Enrique Lopezrodriguez, T Diazsantos, Moshe ElitzurAbstract:We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy Torus models. We compiled high spatial resolution ($\sim 0.3$--$0.7$ arcsec) mid-IR $N$-band spectroscopy, $Q$-band imaging and nuclear near- and mid-IR photometry from the literature. Combining these nuclear near- and mid-IR observations, far-IR photometry and clumpy Torus models, enables us to put constraints on the Torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties; type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the Torus model parameters gives us the first quantitative Torus geometrical view for each subgroup. We find that NHBLR AGN have smaller Torus opening angles and larger covering factors than those of HBLR AGN. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small Torus opening angle and (b) the increased Torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGN.
A Alonsoherrero - One of the best experts on this subject based on the ideXlab platform.
-
alma resolves the Torus of ngc 1068 continuum and molecular line emission
The Astrophysical Journal, 2016Co-Authors: S Garciaburillo, F Combes, Ramos C Almeida, A Usero, M Krips, A Alonsoherrero, Susanne Aalto, V Casasola, L K HuntAbstract:We used the Atacama Large Millimeter Array (ALMA) to map the emission of the CO(6-5) molecular line and the 432 mu m continuum emission from the 300 pc sized circumnuclear disk (CND) of the nearby Seyfert 2 galaxy NGC 1068 with a spatial resolution of similar to 4 pc. These observations spatially resolve the CND and, for the first time, image the dust emission, the molecular gas distribution, and the kinematics from a 7-10 pc diameter disk that represents the submillimeter counterpart of the putative Torus of NGC 1068. We fitted the nuclear spectral energy distribution of the Torus using ALMA and near-and mid-infrared (NIR/MIR) data with CLUMPY Torus models. The mass and radius of the best-fit solution for the Torus are both consistent with the values derived from the ALMA data alone: M-gas(Torus) = (1 +/- 0.3) x 10(5) M-circle dot and R-Torus = 3.5 +/- 0.5 pc. The dynamics of the molecular gas in the Torus show strong non-circular motions and enhanced turbulence superposed on a surprisingly slow rotation pattern of the disk. By contrast with the nearly edge-on orientation of the H2O megamaser disk, we found evidence suggesting that the molecular Torus is less inclined (i = 34 degrees-66 degrees) at larger radii. The lopsided morphology and complex kinematics of the Torus could be the signature of the Papaloizou-Pringle instability, long predicted to likely drive the dynamical evolution of active galactic nuclei tori.
-
alma resolves the Torus of ngc 1068 continuum and molecular line emission
arXiv: Astrophysics of Galaxies, 2016Co-Authors: S Garciaburillo, F Combes, Ramos C Almeida, A Usero, M Krips, A Alonsoherrero, Susanne Aalto, V Casasola, L K HuntAbstract:We have used the Atacama Large Millimeter Array (ALMA) to map the emission of the CO(6-5) molecular line and the 432 {\mu}m continuum emission from the 300 pc-sized circumnuclear disk (CND) of the nearby Seyfert 2 galaxy NGC 1068 with a spatial resolution of ~4 pc. These observations spatially resolve the CND and, for the first time, image the dust emission, the molecular gas distribution, and the kinematics from a 7-10 pc-diameter disk that represents the submillimeter counterpart of the putative Torus of NGC 1068. We fitted the nuclear spectral energy distribution of the Torus using ALMA and near and mid-infrared (NIR/MIR) data with CLUMPY models. The mass and radius of the best-fit solution for the Torus are both consistent with the values derived from the ALMA data alone: Mgas_Torus=(1+-0.3)x10^5 Msun and RTorus=3.5+-0.5 pc. The dynamics of the molecular gas in the Torus show non-circular motions and enhanced turbulence superposed on the rotating pattern of the disk. The kinematic major axis of the CO Torus is tilted relative to its morphological major axis. By contrast with the nearly edge-on orientation of the H2O megamaser disk, we have found evidence suggesting that the molecular Torus is less inclined (i=34deg-66deg) at larger radii. The lopsided morphology and complex kinematics of the Torus could be the signature of the Papaloizou-Pringle instability, long predicted to likely drive the dynamical evolution of active galactic nuclei (AGN) tori.
-
the differences in the Torus geometry between hidden and non hidden broad line active galactic nuclei
The Astrophysical Journal, 2015Co-Authors: Kohei Ichikawa, A Alonsoherrero, C Packham, Cristina Ramos Almeida, Andres Asensio Ramos, O Gonzalezmartin, Enrique LopezrodriguezAbstract:We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGNs) with clumpy Torus models. We compiled high spatial resolution (~0.3–0.7 arcsec) mid-IR (MIR) N-band spectroscopy, Q-band imaging, and nuclear near- and MIR photometry from the literature. Combining these nuclear near- and MIR observations, far-IR photometry, and clumpy Torus models enables us to put constraints on the Torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties: type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the Torus model parameters gives us the first quantitative Torus geometrical view for each subgroup. We find that NHBLR AGNs have smaller Torus opening angles and larger covering factors than HBLR AGNs. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small Torus opening angle and (b) the increased Torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGNs.
-
on the difference of Torus geometry between hidden and non hidden broad line active galactic nuclei
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Kohei Ichikawa, Yoshihiro Ueda, A Alonsoherrero, C Packham, Cristina Ramos Almeida, Andres Asensio Ramos, O Gonzalezmartin, Enrique Lopezrodriguez, T Diazsantos, Moshe ElitzurAbstract:We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy Torus models. We compiled high spatial resolution ($\sim 0.3$--$0.7$ arcsec) mid-IR $N$-band spectroscopy, $Q$-band imaging and nuclear near- and mid-IR photometry from the literature. Combining these nuclear near- and mid-IR observations, far-IR photometry and clumpy Torus models, enables us to put constraints on the Torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties; type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the Torus model parameters gives us the first quantitative Torus geometrical view for each subgroup. We find that NHBLR AGN have smaller Torus opening angles and larger covering factors than those of HBLR AGN. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small Torus opening angle and (b) the increased Torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGN.
Kohei Ichikawa - One of the best experts on this subject based on the ideXlab platform.
-
cooling timescale of dust tori in dying active galactic nuclei
arXiv: Astrophysics of Galaxies, 2017Co-Authors: Kohei Ichikawa, Ryo TazakiAbstract:We estimate the dust Torus cooling timescale once the active galactic nucleus (AGN) is quenched. In a clumpy Torus system, once the incoming photons are suppressed, the cooling timescale of one clump from $T_{\rm dust}=1000$ K to several $10$ K is less than $10$ years, indicating that the dust Torus cooling time is mainly governed by the light crossing time of the Torus from the central engine. After considering the light crossing time of the Torus, the AGN Torus emission at $12~\mu$m becomes over two orders of magnitude fainter within $100$ years after the quenching. We also propose that those "dying" AGN could be found using the AGN indicators with different physical scale $R$ such as $12~\mu$m band luminosity tracing AGN Torus ($R \sim 10$ pc) and the optical [OIII]$\lambda5007$ emission line narrow line regions ($R=10^{2-4}$ pc).
-
the differences in the Torus geometry between hidden and non hidden broad line active galactic nuclei
The Astrophysical Journal, 2015Co-Authors: Kohei Ichikawa, A Alonsoherrero, C Packham, Cristina Ramos Almeida, Andres Asensio Ramos, O Gonzalezmartin, Enrique LopezrodriguezAbstract:We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGNs) with clumpy Torus models. We compiled high spatial resolution (~0.3–0.7 arcsec) mid-IR (MIR) N-band spectroscopy, Q-band imaging, and nuclear near- and MIR photometry from the literature. Combining these nuclear near- and MIR observations, far-IR photometry, and clumpy Torus models enables us to put constraints on the Torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties: type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the Torus model parameters gives us the first quantitative Torus geometrical view for each subgroup. We find that NHBLR AGNs have smaller Torus opening angles and larger covering factors than HBLR AGNs. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small Torus opening angle and (b) the increased Torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGNs.
-
on the difference of Torus geometry between hidden and non hidden broad line active galactic nuclei
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Kohei Ichikawa, Yoshihiro Ueda, A Alonsoherrero, C Packham, Cristina Ramos Almeida, Andres Asensio Ramos, O Gonzalezmartin, Enrique Lopezrodriguez, T Diazsantos, Moshe ElitzurAbstract:We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy Torus models. We compiled high spatial resolution ($\sim 0.3$--$0.7$ arcsec) mid-IR $N$-band spectroscopy, $Q$-band imaging and nuclear near- and mid-IR photometry from the literature. Combining these nuclear near- and mid-IR observations, far-IR photometry and clumpy Torus models, enables us to put constraints on the Torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties; type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the Torus model parameters gives us the first quantitative Torus geometrical view for each subgroup. We find that NHBLR AGN have smaller Torus opening angles and larger covering factors than those of HBLR AGN. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small Torus opening angle and (b) the increased Torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGN.
Enrique Lopezrodriguez - One of the best experts on this subject based on the ideXlab platform.
-
the differences in the Torus geometry between hidden and non hidden broad line active galactic nuclei
The Astrophysical Journal, 2015Co-Authors: Kohei Ichikawa, A Alonsoherrero, C Packham, Cristina Ramos Almeida, Andres Asensio Ramos, O Gonzalezmartin, Enrique LopezrodriguezAbstract:We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGNs) with clumpy Torus models. We compiled high spatial resolution (~0.3–0.7 arcsec) mid-IR (MIR) N-band spectroscopy, Q-band imaging, and nuclear near- and MIR photometry from the literature. Combining these nuclear near- and MIR observations, far-IR photometry, and clumpy Torus models enables us to put constraints on the Torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties: type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the Torus model parameters gives us the first quantitative Torus geometrical view for each subgroup. We find that NHBLR AGNs have smaller Torus opening angles and larger covering factors than HBLR AGNs. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small Torus opening angle and (b) the increased Torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGNs.
-
on the difference of Torus geometry between hidden and non hidden broad line active galactic nuclei
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Kohei Ichikawa, Yoshihiro Ueda, A Alonsoherrero, C Packham, Cristina Ramos Almeida, Andres Asensio Ramos, O Gonzalezmartin, Enrique Lopezrodriguez, T Diazsantos, Moshe ElitzurAbstract:We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy Torus models. We compiled high spatial resolution ($\sim 0.3$--$0.7$ arcsec) mid-IR $N$-band spectroscopy, $Q$-band imaging and nuclear near- and mid-IR photometry from the literature. Combining these nuclear near- and mid-IR observations, far-IR photometry and clumpy Torus models, enables us to put constraints on the Torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties; type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the Torus model parameters gives us the first quantitative Torus geometrical view for each subgroup. We find that NHBLR AGN have smaller Torus opening angles and larger covering factors than those of HBLR AGN. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small Torus opening angle and (b) the increased Torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGN.
