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NuSTAR observations of water megamaser AGN

Masini, A. and Comastri, A. and Baloković, M. and Zaw, I. and Puccetti, S. and Ballantyne, D. R. and Bauer, F. E. and Boggs, S. E. and Brandt, W. N. and Brightman, M. and Christensen, F. E. and Craig, W. W. and Gandhi, P. and Hailey, C. J. and Harrison, F. A. and Koss, M. J. and Madejski, G. and Ricci, C. and Rivers, E. and Stern, D. and Zhang, W. W. (2016) NuSTAR observations of water megamaser AGN. Astronomy and Astrophysics, 589 . Art. No. A59. ISSN 0004-6361. doi:10.1051/0004-6361/201527689.

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Aims. We study the connection between the masing disk and obscuring torus in Seyfert 2 galaxies. Methods. We present a uniform X-ray spectral analysis of the high energy properties of 14 nearby megamaser active galactic nuclei observed by NuSTAR. We use a simple analytical model to localize the maser disk and understand its connection with the torus by combining NuSTAR spectral parameters with the available physical quantities from VLBI mapping. Results. Most of the sources that we analyzed are heavily obscured, showing a column density in excess of ~10^(23) cm^(-2); in particular, 79% are Compton-thick (N_H > 1.5 × 10^(24) cm^(-2)). When using column densities measured by NuSTAR with the assumption that the torus is the extension of the maser disk, and further assuming a reasonable density profile, we can predict the torus dimensions. They are found to be consistent with mid-IR interferometry parsec-scale observations of Circinus and NGC 1068. In this picture, the maser disk is intimately connected to the inner part of the torus. It is probably made of a large number of molecular clouds that connect the torus and the outer part of the accretion disk, giving rise to a thin disk rotating in most cases in Keplerian or sub-Keplerian motion. This toy model explains the established close connection between water megamaser emission and nuclear obscuration as a geometric effect.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Masini, A.0000-0002-7100-9366
Comastri, A.0000-0003-3451-9970
Baloković, M.0000-0003-0476-6647
Puccetti, S.0000-0002-2734-7835
Ballantyne, D. R.0000-0001-8128-6976
Bauer, F. E.0000-0002-8686-8737
Boggs, S. E.0000-0001-9567-4224
Brandt, W. N.0000-0002-0167-2453
Brightman, M.0000-0002-8147-2602
Christensen, F. E.0000-0001-5679-1946
Gandhi, P.0000-0003-3105-2615
Harrison, F. A.0000-0003-2992-8024
Koss, M. J.0000-0002-7998-9581
Ricci, C.0000-0001-5231-2645
Stern, D.0000-0003-2686-9241
Zhang, W. W.0000-0002-1426-9698
Additional Information:© 2016 ESO. Article published by EDP Sciences. Received 3 November 2015; Accepted 9 February 2016; Published online 13 April 2016. We thank the anonymous referee for useful suggestions that helped to improve the paper. This work was supported under NASA Contract NNG08FD60C, and it made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). A.M., A.C., and S.P. acknowledge support from the ASI/INAF grant I/037/12/0-011/13. M.B. acknowledges support from NASA Headquarters under the NASA Earth and Space Science Fellowship Program, grant NNX14AQ07H.We acknowledge support from CONICYT-Chile grants Basal-CATA PFB-06/2007 (F.E.B., C.R.), FONDECYT 1141218 (F.E.B., C.R.), “EMBIGGEN” Anillo ACT1101 (F.E.B., C.R.), and the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS (F. E. B.). W. N. B. acknowledges support from NuSTAR subcontract 44A-1092750.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)I/037/12/0-011/13
NASA Earth and Space Science FellowshipNNX14AQ07H
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1141218
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)Anillo ACT1101
Iniciativa Científica Milenio del Ministerio de Economía, Fomento y TurismoIC120009
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Subject Keywords:masers – galaxies: active – galaxies: Seyfert
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2016-19
Record Number:CaltechAUTHORS:20160318-101742575
Persistent URL:
Official Citation:NuSTAR observations of water megamaser AGN A. Masini, A. Comastri, M. Baloković, I. Zaw, S. Puccetti, et al. , D. R. Ballantyne, F. E. Bauer, S. E. Boggs, W. N. Brandt, M. Brightman, F. E. Christensen, W. W. Craig, P. Gandhi, C. J. Hailey, F. A. Harrison, M. J. Koss, G. Madejski, C. Ricci, E. Rivers, D. Stern and W. W. Zhang A&A, 589 (2016) A59 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65479
Deposited By: Ruth Sustaita
Deposited On:18 Mar 2016 18:58
Last Modified:10 Nov 2021 23:46

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