1. Molecular gas kinematics in the nuclear region of nearby Seyfert galaxies with ALMA
- Author
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Kalliopi Dasyra, J. R. De Medeiros, A. Bewketu Belete, R. Slater, C. Cicone, J. A. Fernández-Ontiveros, Claudio Ricci, Francoise Combes, L. Spinoglio, M. Sirressi, Evanthia Hatziminaoglou, Masatoshi Imanishi, Susanne Aalto, Paola Andreani, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)
- Subjects
Physics ,ISM: kinematics and dynamics ,[PHYS]Physics [physics] ,Active galactic nucleus ,Continuum (design consultancy) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Context (language use) ,galaxies: individual: MCG-06-30-15 ,Astrophysics ,Rotation ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,galaxies: individual: NGC 4968 ,13. Climate action ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,galaxies: structure ,Emission spectrum ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Lindblad resonance ,Line (formation) ,galaxies: individual: NGC 4845 - Abstract
We present the analysis of the molecular gas in the nuclear regions of NGC 4968, NGC 4845, and MCG-06-30-15, with the help of ALMA observations of the CO(2-1) emission line. The aim is to determine the kinematics of the gas in the central (~ 1 kpc) region. We use the 3D-Based Analysis of Rotating Object via Line Observations ($^{3D}$BAROLO) and DiskFit softwares. Circular motions dominate the kinematics of the gas in the central discs, mainly in NGC 4845 and MCG-06-30-15, however there is a clear evidence of non-circular motions in the central ($\sim$ 1 kpc) region of NGC 4845 and NGC 4968. The strongest non-circular motion is detected in the inner disc of NGC 4968 with velocity $\sim 115\, \rm{km\,s^{-1}}$. The bisymmetric model is found to give the best-fit for NGC 4968 and NGC 4845. If the dynamics of NGC 4968 is modeled as a corotation pattern just outside of the bar, the bar pattern speed turns out to be at $\Omega_b$ = $52\, \rm{km\,s^{-1}\,kpc^{-1}}$ the corotation is set at 3.5 kpc and the inner Lindblad resonance (ILR) ring at R = 300pc corresponding to the CO emission ring. The 1.2 mm ALMA continuum is peaked and compact in NGC 4968 and MCG-06-30-15, but their CO(2-1) has an extended distribution. Allowing the CO-to-H$_{2}$ conversion factor $\alpha_{CO}$ between 0.8 and 3.2, typical of nearby galaxies of the same type, the molecular mass M(H$_{2}$) is estimated to be $\sim 3-12\times 10^{7} ~{\rm M_\odot}$ (NGC 4968), $\sim 9-36\times 10^{7}~ {\rm M_\odot}$ (NGC 4845), and $\sim 1-4\times 10^{7}~ {\rm M_\odot}$ (MCG-06-30-15). We conclude that the observed non-circular motions in the disc of NGC 4968 and likely that seen in NGC 4845 is due to the presence of the bar in the nuclear region. At the current spectral and spatial resolution and sensitivity we cannot claim any strong evidence in these sources of the long sought feedback/feeding effect due to the AGN presence., Comment: 14 pages, 11 figures, 3 tables, accepted for publication in the Astronomy & Astrophysics (A&A) journal
- Published
- 2021