The fountain of the luminous infrared galaxy Zw049.057 as traced by its OH megamaser
Journal article, 2024

High-resolution (0″037-0″13 [10-35 pc]) e-MERLIN (λ6-18 cm) and (0″024 [6.5 pc]) ALMA (λ1.1 mm) observations have been used to image OH (hydroxyl) and H2CO (formaldehyde) megamaser emission, and HCN 3 → 2 emission toward the nuclear (< 100 pc) region of the luminous infrared galaxy Zw049.057. Zw049.057 hosts a compact obscured nucleus (CON), and thus represents a class of galaxies that are often associated with inflow and outflow motions. Formaldehyde megamaser emission has been detected toward the nuclear region, ≲30 pc (0″1 $), and traces a structure along the disk major axis. OH megamaser (OHM) emission has been detected along the minor axis of the disk, ~30 pc (0″1 $) from the nucleus, where it exhibits a velocity gradient with extrema of -20 km s-1 southeast (SE) of the disk and -110 km s-1 northwest (NW) of the disk. HCN 3 → 2 emission reveals extended emission, along the disk minor axis out to ~60 pc (0″2 $). Analysis of the minor axis HCN emission reveals high-velocity features extending out to 600 km s-1, redshifted on the SE side and blueshifted on the NW side. We propose that the high-velocity HCN emission traces a fast (> 250 km s-1) and collimated outflow that is enveloped by a wide-angle and slow (~50 km s-1) outflow that is traced by the OHM emission. Analysis of the outflow kinematics suggests that the slow wide-angle outflow will not reach escape velocity and will instead fall back to the galaxy disk, evolving as a so-called fountain flow, while the fast collimated outflow traced by HCN emission will likely escape the nuclear region. We suggest that the absence of OHM emission in the nuclear region is due to high densities there. Even though OHMs associated with outflows are an exception to conventional OHM emission, we expect them to be common in CON sources that host both OHM and H2CO megamasers.

Galaxies: nuclei

Masers

ISM: jets and outflows

Galaxies: evolution

Galaxies: kinematics and dynamics

Galaxies: ISM

Author

Boy Lankhaar

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Leiden University

Susanne Aalto

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Clare Wethers

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

J. Moldon

University of Manchester

Institute of Astrophysics of Andalusia (IAA)

R. J. Beswick

University of Manchester

Mark Gorski

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Sabine König

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Chentao Yang

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

J. G. Mangum

National Radio Astronomy Observatory

J. S. Gallagher

Macalester College

University of Wisconsin Madison

F. Combes

Paris Observatory

D. Rigopoulou

European University Cyprus

University of Oxford

E. Gonzalez-Alfonso

University of Alcalá

S. Muller

I. García-Bernete

University of Oxford

C. Henkel

Max Planck Society

Y. Nishimura

University of Tokyo

C. Ricci

Diego Portales University

Beijing University of Technology

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 689 A163

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Swedish Research Council (VR) (2021-00339), 2021-07-01 -- 2024-06-30.

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European Research Council (ERC) (789410), 2018-10-01 -- 2023-09-30.

Subject Categories

Subatomic Physics

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

DOI

10.1051/0004-6361/202450065

More information

Latest update

9/27/2024