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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 606564.0, MPI für Astronomie / Publikationen_mpia
Submillimeter Array/Plateau de Bure Interferometer multiple line observations of the nearby Seyfert 2 galaxy NGC 1068: shock-related gaskinematics and heating in the central 100 pc?
Authors:Krips, M.; Martín, S.; Eckart, A.; Neri, R.; García-Burillo, S.; Matsushita, S.; Peck, A.; Stoklasová, I.; Petitpas, G.; Usero, A.; Combes, F.; Schinnerer, E.; Humphreys, E.; Baker, A. J.
Date of Publication (YYYY-MM-DD):2011
Journal Abbrev.:The Astrophysical Journal
Issue / Number:1
Audience:Not Specified
Abstract / Description:We present high angular resolution (0farcs5-2farcs0) observations of the millimeter continuum and the 12CO(J = 3-2), 13CO(J = 3-2), 13CO(J = 2-1), C18O(J = 2-1), HCN(J = 3-2), HCO+(J = 4-3), and HCO+(J = 3-2) line emission in the circumnuclear disk (r <~ 100 pc) of the prototypical Seyfert 2 galaxy NGC 1068, carried out with the Submillimeter Array. We also include in our analysis new 13CO(J = 1-0) and improved 12CO(J = 2-1) observations of NGC 1068 at high angular resolution (1farcs0-2farcs0) and sensitivity, conducted with the Institute de Radioastronomie Millimetrique Plateau de Bure Interferometer. Based on the complex dynamics of the molecular gas emission indicating non-circular motions in the central ~100 pc, we propose a scenario in which part of the molecular gas in the circumnuclear disk of NGC 1068 is blown radially outward as a result of shocks. This shock scenario is further supported by quite warm (T kin >= 200 K) and dense (n(H2) sime 104 cm-3) gas constrained from observed molecular line ratios. The HCN abundance in the circumnuclear disk is found to be [HCN]/[12CO] ≈ 10-3.5. This is slightly higher than the abundances derived for Galactic and extragalactic star-forming/starbursting regions. This result lends further support to X-ray-enhanced HCN formation in the circumnuclear disk of NGC 1068 as suggested by earlier studies. The HCO+ abundance ([HCO+]/[12CO] ≈ 10-5) appears to be somewhat lower than that of Galactic and extragalactic star-forming/starbursting regions. When trying to fit the centimeter-to-millimeter continuum emission by different thermal and non-thermal processes, it appears that electron-scattered synchrotron emission yields the best results while thermal free-free emission seems to overpredict the millimeter continuum emission. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).
Free Keywords:galaxies: active; galaxies: individual: NGC 1068; galaxies: ISM; galaxies: kinematics and dynamics; galaxies: nuclei; galaxies: Seyfert; radio continuum: galaxies; radio lines: galaxies; submillimeter: galaxies
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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