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: kinematics and dynamics
Galaxies: evolution
Galaxies: ISM
ISM: jets and outflows
Masers
Galaxies: nuclei
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
Institute of Astrophysics of Andalusia (IAA)
University of Manchester
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
University of Oxford
European University Cyprus
E. Gonzalez-Alfonso
University of Alcalá
Sebastien Muller
Chalmers, Space, Earth and Environment, Onsala Space Observatory
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 A163A polarized view on stars, planets and life
Swedish Research Council (VR) (2021-00339), 2021-07-01 -- 2024-06-30.
Exploring the Hidden Dusty Nuclei of Galaxies (HIDDeN)
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