학술논문
The Megamaser Cosmology Project − XII. VLBI imaging of H2 O maser emission in three active galaxies and the effect of AGN winds on disc dynamics.
Document Type
Article
Author
Source
Subject
*ACTIVE galaxies
*VERY long baseline interferometry
*MASERS
*ACTIVE galactic nuclei
*DISC brakes
*BLACK holes
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Language
ISSN
0035-8711
Abstract
We present very long baseline interferometry (VLBI) images and kinematics of water maser emission in three active galaxies: NGC 5728, Mrk 1, and IRAS 08452–0011. IRAS 08452–0011, at a distance of ∼200 Mpc, is a triple-peaked H2O megamaser, consistent with a Keplerian rotating disc, indicating a black hole mass of (3.3 |$\pm 0.2)\times 10^{7}\, \mathrm{ M}_{\odot }$|. NGC 5728 and Mrk 1 display double-peaked spectra, and VLBI imaging reveals complicated gas kinematics that do not allow for a robust determination of black hole mass. We show evidence that the masers in NGC 5728 are in a wind while the Mrk 1 maser system has both disc and outflow components. We also find that disturbed morphology and kinematics are a ubiquitous feature of all double-peaked maser systems, implying that these maser sources may reside in environments where active galactic nucleus (AGN) winds are prominent at ∼1 pc scale and have significant impact on the masing gas. Such AGNs tend to have black hole masses |$M_{\rm BH}\, \lt$| 8 × 106 M⊙ and Eddington ratios |$\lambda _{\rm Edd}\, \gtrsim$| 0.1, while the triple-peaked megamasers show an opposite trend. [ABSTRACT FROM AUTHOR]