Leon, S. and Eckart, A. and Laine, S. and Kotilainen, J. K. and Schinnerer, E. and Lee, S. -W. and Krips, M. and Reunanen, J. and Scharwächter, J. (2007) Nuclear starburst-drive evolution of the central region in NGC 6764. Astronomy and Astrophysics, 473 (3). pp. 747-759. ISSN 0004-6361 http://resolver.caltech.edu/CaltechAUTHORS:20100420-151553461
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Aims.We study the CO and the radio continuum emission in an active galaxy to analyze the interplay between the central activity and the molecular gas. Methods.We present new high-resolution observations of the ^(12)CO(1-0) and ^(12)CO(2-1) emission lines, and 3.5 cm and 20 cm radio continuum emission in the central region of the LINER/starburst galaxy NGC 6764. Results.The galaxy has an outflow morphology in radio continuum, spatially coincident with the CO and Hα emission, and centered slightly off the radio continuum peak at the LINER nucleus. The total molecular gas mass in the center is about 7 × 10^8 M_☉, using a CO luminosity to total molecular gas conversion factor that is three times lower than the standard one. ^(12)CO(1-0) emission is found near the boundaries of the radio continuum emission cone. The outflow has a projected expansion velocity of 25 km s^(-1) relative to the systemic velocity of NGC 6764. About 4 × 10^6 M_☉ of molecular gas is detected in the outflow. The approximate location (~1 kpc) of the dynamical inner Lindblad resonance has been derived from the rotation curve. The peak of the CO emission is slightly (<200 pc) offset from the peak of the radio continuum. Conclusions.The molecular gas has most likely been ejected by the stellar winds from the recent starburst, but the CO line ratios show indication of an interaction with the AGN. The energy released by the nuclear starburst is sufficient to explain the observed outflow, even if the data cannot exclude the AGN from being the major energy source. Comparison of the outflow with hydrodynamical simulations suggests that the nuclear starburst is 3-7 Myr old and the bubble-like outflow is still confined and not freely expanding.
|Additional Information:||© 2007 ESO. Received 20 July 2006; accepted 29 June 2007. We thank the anonymous referee for a careful reading and very detailed report which helped to improve this paper significantly. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. During part of this research S. Leon was supported by a Marie Curie Individual Fellowship contract HPMF-CT-20002-01734 from the European Union. We would like to thank David Frayer and Eric Wilcots for providing their Hα and HI data, respectively.|
|Subject Keywords:||ISM: jets and outflows; galaxies: active; ISM: kinematics and dynamics; ISM: individual: objects: NGC 6764; radio lines: galaxies|
|Official Citation:||Nuclear starburst-driven evolution of the central region in NGC 6764 S. Leon, A. Eckart, S. Laine, J. K. Kotilainen, E. Schinnerer, S.-W. Lee, M. Krips, J. Reunanen and J. Scharwächter A&A 473 (3) 747-759 (2007) DOI: 10.1051/0004-6361:20066075|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||20 Apr 2010 23:33|
|Last Modified:||26 Dec 2012 11:59|
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