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X-ray spectral and eclipsing model of the clumpy obscurer in active galactic nuclei

Buchner, Johannes and Brightman, Murray and Nandra, Kirpal and Nikutta, Robert and Bauer, Franz E. (2019) X-ray spectral and eclipsing model of the clumpy obscurer in active galactic nuclei. Astronomy and Astrophysics, 629 . Art. No. A16. ISSN 0004-6361.

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We present a unification model for a clumpy obscurer in active galactic nuclei (AGN) and investigate the properties of the resulting X-ray spectrum. Our model is constructed to reproduce the column density distribution of the AGN population and cloud eclipse events in terms of their angular sizes and frequency. We developed and released a generalised Monte Carlo X-ray radiative transfer code, XARS, to compute X-ray spectra of obscurer models. The geometry results in strong Compton scattering, causing soft photons to escape also along Compton-thick sight lines. This makes our model spectra very similar to our TORUS previous model. However, only if we introduce an additional Compton-thick reflector near the corona, we achieve good fits to NuSTAR spectra. This additional component in our model can be interpreted as part of the dust-free broad-line region, an inner wall or rim, or a warped disk. It cannot be attributed to a simple disk because the reflector must simultaneously block the line of sight to the corona and reflect its radiation. We release our model as an Xspec table model and present corresponding CLUMPY infrared spectra, paving the way for self-consistent multi-wavelength analyses.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper associated to Fig. 4 associated to Fig. 4
Buchner, Johannes0000-0003-0426-6634
Brightman, Murray0000-0002-8147-2602
Nandra, Kirpal0000-0002-7150-9192
Nikutta, Robert0000-0002-7052-6900
Bauer, Franz E.0000-0002-8686-8737
Additional Information:© 2019 ESO. Article published by EDP Sciences. Received 3 December 2018; Accepted 18 July 2019; Published online 27 August 2019. We thank the anonymous referee for careful reading of the manuscript and their insightful comments. JB thanks Marc Schartmann and Leonard Burtscher for discussions on tori in the infrared. JB thanks Eva Lefa for sharing her Monte Carlo code to verify our Compton scattering implementation. JB thanks Mislav Baloković for insightful conversations. We acknowledge support from the CONICYT-Chile grants Basal-CATA PFB-06/2007 & AFB-170002 (JB, FEB), FONDECYT Regular 1141218 (FEB), FONDECYT Postdoctorados 3160439 (JB) and the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS (JB, FEB). This research was supported by the DFG cluster of excellence “Origin and Structure of the Universe”.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1141218
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)3160439
Iniciativa Científica Milenio del Ministerio de Economía, Fomento y TurismoIC120009
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Subject Keywords:galaxies: active – X-rays: galaxies – methods: numerical
Record Number:CaltechAUTHORS:20190809-153450175
Persistent URL:
Official Citation:X-ray spectral and eclipsing model of the clumpy obscurer in active galactic nuclei. Johannes Buchner, Murray Brightman, Kirpal Nandra, Robert Nikutta and Franz E. Bauer. A&A, 629 (2019) A16. DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97734
Deposited By: Tony Diaz
Deposited On:09 Aug 2019 22:51
Last Modified:03 Oct 2019 21:34

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