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Recent observations of NGC 1068 and other AGN support the idea of a geometrically and optically thick dust torus surrounding the central supermassive black hole and accretion disk of AGN. In type 2 AGN, the torus is seen roughly edge-on,…

Astrophysics · Physics 2007-05-23 S. F. Hoenig , T. Beckert , K. Ohnaka , G. Weigelt

We present Spitzer infrared spectra and ultra-violet to mid-infrared spectral energy distributions (SEDs) of 25 luminous type 1 quasars at z \sim 2. In general, the spectra show a bump peaking around 3 {\mu}m, and the 10 {\mu}m silicate…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Rajesh P. Deo , Gordon T. Richards , Robert Nikutta , Moshe Elitzur , Sarah C. Gallagher , Zeljko Ivezic , Dean Hines

Constrained adaptive filtering algorithms inculding constrained least mean square (CLMS), constrained affine projection (CAP) and constrained recursive least squares (CRLS) have been extensively studied in many applications. Most existing…

Machine Learning · Statistics 2016-12-15 Siyuan Peng , Badong Chen , Lei Sun , Zhiping Lin , Wee Ser

We apply XCLUMPY, an X-ray spectral model from a clumpy torus in an active galactic nucleus (AGN), to the broadband X-ray spectra of 10 obscured AGNs observed with both Suzaku and NuSTAR. The infrared spectra of these AGNs were analyzed…

High Energy Astrophysical Phenomena · Physics 2020-07-08 Atsushi Tanimoto , Yoshihiro Ueda , Hirokazu Odaka , Shoji Ogawa , Satoshi Yamada , Toshihiro Kawaguchi , Kohei Ichikawa

The clustering of bounded data presents unique challenges in statistical analysis due to the constraints imposed on the data values. This paper introduces a novel method for model-based clustering specifically designed for bounded data.…

Methodology · Statistics 2025-05-16 Luca Scrucca

Cluster-scale strong lensing is a powerful tool for exploring the properties of dark matter and constraining cosmological models. However, due to the complex parameter space, pixelized strong lens modeling in galaxy clusters is…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-07 Yushan Xie , Huanyuan Shan , Nan Li , Ran Li , Eric Jullo , Chen Su , Xiaoyue Cao , Jean-Paul Kneib , Ana Acebron , Mengfan He , Ji Yao , Chunxiang Wang , Jiadong Li , Yin Li

We derive the properties of dusty tori in Active Galactic Nuclei (AGN) from the comparison of observed Spectral Energy Distributions (SEDs) of SDSS quasars and a precomputed grid of torus models. The observed SEDs comprise SDSS photometry,…

We have developed the dynamical model of a clumpy torus in an active galactic nucleus (AGN) and compared to recent ALMA observations. We present $N$-body simulations of a torus in the field of a supermassive black hole (SMBH), made of up to…

Astrophysics of Galaxies · Physics 2021-02-25 E. Yu. Bannikova , A. V. Sergeyev , N. A. Akerman , P. P. Berczik , M. V. Ishchenko , M. Capaccioli , V. S. Akhmetov

The paper considers the problem of anomaly detection in 3D images of fibre materials. The spatial Stochastic Expectation Maximisation algorithm and Adaptive Weights Clustering are applied to solve this problem. The initial 3D grey scale…

Coronal-Line Forest Active Galactic Nuclei (CLiF AGN) are characterized by strong, high-ionization lines, which are in contrast to what is found in typical AGNs. Here, we carry out an infrared analysis aimed at understanding the spectral…

Astrophysics of Galaxies · Physics 2023-07-05 F. C. Cerqueira-Campos , A. Rodríguez-Ardila , S. Panda , R. Riffel , L. G. Dahmer-Hahn , M. Marinello

Dust plays a pivotal role in determining the observed spectral energy distribution (SED) of galaxies. Yet our understanding of dust attenuation is limited and our observations suffer from the dust-metallicity-age degeneracy in SED fitting…

Astrophysics of Galaxies · Physics 2022-06-22 Gautam Nagaraj , John C. Forbes , Joel Leja , Daniel Foreman-Mackey , Christopher C. Hayward

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…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Atsushi Tanimoto , Yoshihiro Ueda , Hirokazu Odaka , Toshihiro Kawaguchi , Yasushi Fukazawa , Taiki Kawamuro

We characterize for the first time the torus properties of an ultra-hard X-ray (14-195 keV) volume-limited (DL<40 Mpc) sample of 24 Seyfert (Sy) galaxies (BCS40 sample). The sample was selected from the Swift/BAT nine month catalog. We use…

According to unified schemes of Active Galactic Nuclei (AGN), the central engine is surrounded by dusty, optically thick clouds in a toroidal structure. We have recently developed a formalism that for the first time takes proper account of…

Astrophysics · Physics 2009-11-13 Maia Nenkova , Matthew M. Sirocky , Zeljko Ivezic , Moshe Elitzur

We consider the utilization of a computational model to guide the optimal acquisition of experimental data to inform the stochastic description of model input parameters. Our formulation is based on the recently developed consistent…

Computation · Statistics 2021-05-04 Scott N. Walsh , Tim M. Wildey , John D. Jakeman

We use 3-D radiative transfer models to show the effects of clumpy circumstellar material on the observed infrared colors of high mass stars embedded in molecular clouds. We highlight differences between 3-D clumpy and 1-D smooth models…

Astrophysics · Physics 2009-11-13 R. Indebetouw , B. A. Whitney , K. E. Johnson , K. wood

Bayesian optimization (BO) is a model-based approach to sequentially optimize expensive black-box functions, such as the validation error of a deep neural network with respect to its hyperparameters. In many real-world scenarios, the…

Machine Learning · Statistics 2019-10-17 Valerio Perrone , Iaroslav Shcherbatyi , Rodolphe Jenatton , Cedric Archambeau , Matthias Seeger

As the quality of the available galaxy cluster data improves, the models fitted to these data might be expected to become increasingly complex. Here we present the Bayesian approach to the problem of cluster data modelling: starting from…

Astrophysics · Physics 2009-11-10 P. J. Marshall , M. P. Hobson , A. Slosar

In this paper, we try to explain the observed correlation between the covering factor (CF) of hot dust and the properties of active galactic nuclei (AGNs), e.g., the bolometric luminosity ($L_{\rm{bol}}$) and black hole mass…

Astrophysics of Galaxies · Physics 2015-12-09 Jian-Jian He , Yuan Liu , Shuang-Nan Zhang

We present near-to-mid-infrared spectral energy distributions (SEDs) for 21 Seyfert galaxies, using subarcsecond resolution imaging data. Our aim is to compare the properties Seyfert 1 (Sy1) and Seyfert 2 (Sy2) tori using clumpy torus…