JOURNAL ARTICLE

Very long baseline interferometry imaging of H2O maser emission in the nearby radio galaxy NGC 4261.

  • Published In: Publications of the Astronomical Society of Japan, 2023, v. 75, n. 4. P. 722 1 of 3

  • Database: Academic Search Ultimate 2 of 3

  • Authored By: Sawada-Satoh, Satoko; Kawakatu, Nozomu; Niinuma, Kotaro; Kameno, Seiji 3 of 3

Abstract

This article focuses on dual-frequency very long baseline interferometry (VLBI) observations of the 22 GHz H₂O maser emission in the nearby radio-loud galaxy NGC 4261, aiming to determine the maser's location and kinematics in relation to the active galactic nucleus (AGN). The H₂O maser emission is marginally detected slightly red-shifted relative to the systemic velocity and is spatially coincident with the free–free absorbed receding jet, suggesting it arises from the near side of a circumnuclear obscuring disk amplifying background continuum emission. The maser's broad line width is attributed to complex gas motions near the supermassive black hole, including infall, turbulence, and outflow, consistent with a multi-phase disk model similar to that proposed for the radio-loud megamaser source NGC 1052. An alternative jet–cloud interaction scenario is considered but does not fully explain the exclusive association of the maser emission with the optically thick receding jet region.

Additional Information

  • Source:Publications of the Astronomical Society of Japan. 2023/08, Vol. 75, Issue 4, p722
  • Document Type:Article
  • Subject Area:Engineering
  • Publication Date:2023
  • ISSN:0004-6264
  • DOI:10.1093/pasj/psad032
  • Accession Number:169851141
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