NuSTAR observations of water megamaser AGN

A. Masini, A. Comastri, M. Baloković, Ingyin Zaw, S. Puccetti, 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. SternW. W. Zhang

Research output: Contribution to journalArticle

Abstract

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 ∼1023 cm-2; in particular, 79% are Compton-thick (NH > 1.5 × 1024 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.

Original languageEnglish (US)
Article numberA59
JournalAstronomy and Astrophysics
Volume589
DOIs
StatePublished - May 1 2016

Fingerprint

masers
water
very long baseline interferometry
interferometry
spectral analysis
very long base interferometry
rotating disks
occultation
molecular clouds
accretion
active galactic nuclei
accretion disks
spectrum analysis
galaxies
energy
profiles
x rays
effect
method
parameter

Keywords

  • galaxies: active
  • galaxies: Seyfert
  • masers

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Masini, A., Comastri, A., Baloković, M., Zaw, I., Puccetti, S., Ballantyne, D. R., ... Zhang, W. W. (2016). NuSTAR observations of water megamaser AGN. Astronomy and Astrophysics, 589, [A59]. https://doi.org/10.1051/0004-6361/201527689

NuSTAR observations of water megamaser AGN. / Masini, A.; Comastri, A.; Baloković, M.; Zaw, Ingyin; Puccetti, S.; Ballantyne, D. R.; Bauer, F. E.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Harrison, F. A.; Koss, M. J.; Madejski, G.; Ricci, C.; Rivers, E.; Stern, D.; Zhang, W. W.

In: Astronomy and Astrophysics, Vol. 589, A59, 01.05.2016.

Research output: Contribution to journalArticle

Masini, A, Comastri, A, Baloković, M, Zaw, I, Puccetti, S, Ballantyne, DR, Bauer, FE, Boggs, SE, Brandt, WN, Brightman, M, Christensen, FE, Craig, WW, Gandhi, P, Hailey, CJ, Harrison, FA, Koss, MJ, Madejski, G, Ricci, C, Rivers, E, Stern, D & Zhang, WW 2016, 'NuSTAR observations of water megamaser AGN', Astronomy and Astrophysics, vol. 589, A59. https://doi.org/10.1051/0004-6361/201527689
Masini A, Comastri A, Baloković M, Zaw I, Puccetti S, Ballantyne DR et al. NuSTAR observations of water megamaser AGN. Astronomy and Astrophysics. 2016 May 1;589. A59. https://doi.org/10.1051/0004-6361/201527689
Masini, A. ; Comastri, A. ; Baloković, M. ; Zaw, Ingyin ; Puccetti, S. ; Ballantyne, D. R. ; Bauer, F. E. ; Boggs, S. E. ; Brandt, W. N. ; Brightman, M. ; Christensen, F. E. ; Craig, W. W. ; Gandhi, P. ; Hailey, C. J. ; Harrison, F. A. ; Koss, M. J. ; Madejski, G. ; Ricci, C. ; Rivers, E. ; Stern, D. ; Zhang, W. W. / NuSTAR observations of water megamaser AGN. In: Astronomy and Astrophysics. 2016 ; Vol. 589.
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AU - Masini, A.

AU - Comastri, A.

AU - Baloković, M.

AU - Zaw, Ingyin

AU - Puccetti, S.

AU - Ballantyne, D. R.

AU - Bauer, F. E.

AU - Boggs, S. E.

AU - Brandt, W. N.

AU - Brightman, M.

AU - Christensen, F. E.

AU - Craig, W. W.

AU - Gandhi, P.

AU - Hailey, C. J.

AU - Harrison, F. A.

AU - Koss, M. J.

AU - Madejski, G.

AU - Ricci, C.

AU - Rivers, E.

AU - Stern, D.

AU - Zhang, W. W.

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N2 - 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 ∼1023 cm-2; in particular, 79% are Compton-thick (NH > 1.5 × 1024 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.

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