Dust Emission From a Parsec-Scale Structure in the Seyfert 1 Nucleus of NGC 4151

Burtscher, L.; Jaffe, W.; Raban, D.; Meisenheimer, K.; Tristram, K.; Röttgering, H. J. A.

doi:10.1088/0004-637x/705/1/l53

Cited by 72 publications

(78 citation statements)

References 26 publications

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“…The most promising tool for this task is IR interferometry, which was already successfully used for a number of nearby objects (Swain et al 2003;Wittkowski et al 2004;Weigelt et al 2004;Jaffe et al 2004;Poncelet et al 2006;Meisenheimer et al 2007;Tristram et al 2007Tristram et al , 2009Beckert et al 2008;Raban et al 2009;Burtscher et al 2009;Kishimoto et al 2009b). However, except for reconstructed images of NGC 1068 obtained from Speckle interferometry (Weigelt et al 2004), long-baseline interferometry usually provides spatial information coded as Fourier space observables, i.e.…”

Section: Interferometry Of Dust Torimentioning

confidence: 99%

The dusty heart of nearby active galaxies

Hönig

Kishimoto

2010

A&A

200

221

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With the possibilities of high spatial resolution imaging and spectroscopy as well as infrared (IR) interferometry, the dusty environments (= "dusty torus") of active galactic nuclei (AGN) are now in reach of observations. Following our Paper I on ground-based mid-IR spectro-photometry, we present an upgrade to our radiative transfer model of three-dimensional clumpy dust tori. The upgrade with respect to earlier work concerns an improved handling of the diffuse radiation field in the torus, which is approximated by a statistical approach. The models are presented as tools to translate classical and interferometric observations into characteristic properties of the dust distribution. We compare model spectral energy distributions (SEDs) for different chemical and grain-size compositions of the dust and find that clouds with standard interstellar matter (ISM) dust and optical depth τ V ∼ 50 appear in overall agreement with observed IR SEDs. By studying parameter dependencies, it is shown that type 1 AGN SEDs, in particular the mid-IR spectral index, can be used to constrain the radial dust cloud distribution power law index a, while other parameters are more difficult to assess using SEDs only. Interferometry adds important additional information for modeling when it is interpreted concurrently with the SED. Although type 2 AGN can in principle be used to constrain model parameters as well, obscuration effects make the analysis more ambiguous. We propose a simple, interferometry-based method to distinguish between "compact" and "extended" radial dust distributions without detailed modeling of the data and introduce a way to easily determine individual or sample average model parameters using the observed optical depth in the silicate feature and the mid-IR spectral index.

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Section: Interferometry Of Dust Torimentioning

confidence: 99%

The dusty heart of nearby active galaxies

Hönig

Kishimoto

2010

A&A

200

221

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“…In the midinfrared, Jaffe et al (2004) spatially resolved a parsec-sized torus-shaped distribution of dust grains in the same galaxy, where a small hot structure is embedded in a colder (320 K) dusty cocoon extending up to 3.4 pc in diameter. Further fluxlimited interferometric studies of nearby quasars, using the MIDinfrared Interferometric instrument (MIDI) at the Very Large Telescope Interferometer (VLTI; see, e.g., Tristram et al 2007;Burtscher et al 2009Burtscher et al , 2013Tristram et al 2014) or the Keck interferometer (Swain et al 2003;Kishimoto et al 2009a), definitively confirmed the existence of the dusty torus, if with large differences within the sample.…”

Section: Introductionmentioning

confidence: 98%

Polarized radiative transfer modeling of warped and clumpy dusty tori

Marin

Schartmann

2017

A&A

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Context. Active galactic nuclei (AGN) are anisotropic objects surrounded by an optically thick equatorial medium whose true geometry still defies observers. Aims. We aim to explore the optical scattering-induced polarization that emerges from clumpy and warped dusty tori to check whether they can fit the unified model predictions. Methods. We ran polarized radiative transfer simulations in a set of warped and non-warped clumpy tori to explore the differences induced by distorted dust distributions. We then included warped tori in a more complex model representative of an AGN to check, using polarimetry and imaging methods, whether warps can reproduce the expected polarization dichotomy between Seyfert-I and Seyfert-II AGN. Results. The main results from our simulations highlight that isolated warped structures imprint the polarization degree and angle with distinctive signatures at Seyfert-I orientations. Included in an AGN model, the signatures of warps are easily (but not always) washed out by multiple scattering in a clumpy environment. Imaging polarimetry may help to detect warped tori, but we prove that warps can exist in AGN circumnuclear regions without contradicting observations. Conclusions. Two warped tori with a non-significant difference in geometry in terms of photometry or spectroscopy can have entirely different signatures in polarimetry. Testing the geometry of any alternative model to the usual dusty torus using polarized radiative transfer is a necessary approach to verify or reject a hypothesis.

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“…early results on Seyfert 2 galaxies by Jaffe et al 2004; radio galaxy, Meisenheimer et al 2007; type 1 AGNs, Beckert et al 2008;Kishimoto et al 2009b;Burtscher et al 2009; snapshot survey, Tristram et al 2009). In the near-IR, after the very early results for the brightest Seyfert 1 galaxy NGC 4151 (Swain et al 2003) and Seyfert 2 galaxy NGC 1068 (Wittkowski et al 2004), long-baseline interferometry has now started to explore the innermost dusty structure extensively at milli-arcsec (mas) resolution (Kishimoto et al 2009a, hereafter Paper I; Pott et al 2010).…”

Section: Introductionmentioning

confidence: 99%

The innermost dusty structure in active galactic nuclei as probed by the Keck interferometer

Kishimoto

Hönig

Antonucci

et al. 2011

A&A

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We are now exploring the inner region of type 1 active galactic nuclei (AGNs) with the Keck interferometer in the near-infrared. Adding to the four targets previously studied, we report measurements of the K-band (2.2 μm) visibilities for four more targets, namely AKN120, IC 4329A, Mrk6, and the radio-loud QSO 3C 273 at z = 0.158. The observed visibilities are quite high for all the targets, which we interpret as an indication of the partial resolution of the dust sublimation region. The effective ring radii derived from the observed visibilities scale approximately with L 1/2 , where L is the AGN luminosity. Comparing the radii with those from independent optical-infrared reverberation measurements, these data support our previous claim that the interferometric ring radius is either roughly equal to or slightly larger than the reverberation radius. We interpret the ratio of these two radii for a given L as an approximate probe of the radial distribution of the inner accreting material. We show tentative evidence that this inner radial structure might be closely related to the radio-loudness of the central engine. Finally, we re-observed the brightest Seyfert 1 galaxy NGC 4151. Its marginally higher visibility at a shorter projected baseline, compared to our previous measurements obtained one year before, further supports the partial resolution of the inner structure. We did not detect any significant change in the implied emission size when the K-band flux was brightened by a factor of 1.5 over a time interval of one year.

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Dust Emission From a Parsec-Scale Structure in the Seyfert 1 Nucleus of NGC 4151

Cited by 72 publications

References 26 publications

The dusty heart of nearby active galaxies

The dusty heart of nearby active galaxies

Polarized radiative transfer modeling of warped and clumpy dusty tori

The innermost dusty structure in active galactic nuclei as probed by the Keck interferometer

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