A plausible link between dynamically unsettled molecular gas and the radio jet in NGC 6328

¹ National Observatory of Athens (NOA), Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS), 15236 Athens, Greece
e-mail: mpapaxristou@noa.gr
² Department of Astrophysics, Astronomy & Mechanics, Faculty of Physics, National and Kapodistrian University of Athens, Panepistimiopolis Zografou 15784, Greece
³ Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Via Fosso del Cavaliere 100, 00133 Roma, Italy
⁴ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan 1, 44001 Teruel, Spain
⁵ Instituto de Astrofísica de Canarias, Calle Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
⁶ Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
⁷ Cardiff Hub for Astrophysics Research & Technology, School of Physics & Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA, UK
⁸ Observatoire de Paris, LERMA, Collège de France, CNRS, PSL Univ., Sorbonne Univ., 75014 Paris, France
⁹ Aix-Marseille Univ., CNRS, CNES, LAM, Marseille, France

Received: 20 March 2023
Accepted: 5 September 2023

Abstract

We report the detection of outflowing molecular gas at the center of the nearby radio galaxy NGC6328 (z = 0.014), which has a gigahertz-peaked spectrum radio core and a compact (2 pc) young double radio lobe tracing jet. Utilizing Atacama Large Millimeter/submillimeter Array (ALMA) CO(3 − 2) and CO(2 − 1) observations, as well as a novel code developed to fit the 3D gas distribution and kinematics, to study the molecular gas kinematics, we find that the bulk of the gas is situated within a highly warped disk structure, most likely the result of a past merger event. Our analysis further uncovers, within the inner regions of the gas distribution (R < 300 pc) and at a position angle aligning with that of the radio jet (150°), the existence of two anti-diametric molecular gas structures kinematically detached from the main disk. These structures most likely trace a jet-induced cold gas outflow with a total lower limit mass of 2 × 10⁶ M_⊙ mass, corresponding to an outflow rate of 2 M_⊙ yr⁻¹ and a kinetic power of 2.7 × 10⁴⁰ erg s⁻¹. The energy required to maintain such a molecular outflow is aligned with the mechanical power of the jet.