Suchergebnisse

Mergers of galaxies are an important mode for galaxy evolution because they serve as an efficient trigger of powerful starbursts. However, observational studies of molecular gas properties during their early stages are scarce. We present interferometric CO(2-1) maps of two luminous infrared galaxies, NGC 3110 and NGC 232, obtained with the Submillimeter Array with ∼1 kpc resolution. While NGC 3110 is a spiral galaxy interacting with a minor (14:1 stellar mass) companion, NGC 232 is interacting with a similarly sized object. We find that such interactions in these galaxies have likely induced enhancements in the molecular gas content and central concentrations, partly at the expense of atomic gas. The obtained molecular gas surface densities in their circumnuclear regions are Σ10 M pc, higher than in noninteracting objects by an order of magnitude. Gas depletion times of 0.5-1 Gyr are found for the different regions, lying in between noninteracting disk galaxies and the starburst sequence. In the case of NGC 3110, the spiral arms show on average 0.5 dex shorter depletion times than in the circumnuclear regions if we assume a similar H-CO conversion factor. We show that even in the early stages of the interaction with a minor companion, a starburst is formed along the circumnuclear region and spiral arms, where a large population of SSCs is found (∼350), and at the same time a large central gas concentration is building up that might be the fuel for an active galactic nucleus. The main morphological properties of the NGC 3110 system are reproduced by our numerical simulations and allow us to estimate that the current epoch of the interaction is at ∼150 Myr after closest approach.© 2018. The American Astronomical Society. All rights reserved. ; We thank the referee for the careful reading and valuable suggestions that helped to improve this paper substantially. This research 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. We acknowledge the usage of the HyperLeda database. (http://leda.univ-lyon1.fr). We thank Dr. T. Hattori and Dr. H. Schmitt for kindly providing Ha maps used in this paper to derive the SF laws. D.E. was supported by a Marie Curie International Fellowship within the Sixth European Community Framework Programme (MOIF-CT-2006-40298). S.V. acknowledges support by the research projects AYA2014-53506-P and AYA2017-84897-P from the Spanish Ministerio de Economia y Competitividad, from the European Regional Development Funds (FEDER) and the Junta de Andalucia (Spain) grants FQM108. T.S. acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 694343). L.V.M. acknowledges support from the grant AYA2015-65973-C3-1-R (MINECO/FEDER, UE). S. Matsushita is supported by the Ministry of Science and Technology (MOST) of Taiwan, MOST 106-2112-M-001-011 and 107-2119-M-001-020. M.A.F. is grateful for financial support from the CONICYT Astronomy Program CAS-CONICYT project No. CAS17002, sponsored by the Chinese Academy of Sciences (CAS), through a grant to the CAS South America Center for Astronomy (CASSACA) in Santiago, Chile. This research made use of Astropy, a community-developed core Python. (http://www.python.org) package for Astronomy (Astropy Collaboration et al. 2013; The Astropy Collaboration et al. 2018); ipython (Perez & Granger 2007); matplotlib (Hunter 2007); APLpy, an opensource plotting package for Python (Robitaille & Bressert 2012) and NumPy (Van Der Walt et al. 2011). We utilized the pynbody python package (Pontzen et al. 2013) for post-processing and analyzing of the tipsy files created by gasoline2. Special thanks to the authors of gasoline2 (Wadsley et al. 2017) for providing the numerical code used to perform the simulations. Part of this work was achieved using the grant of Visiting Scholars Program supported by the Research Coordination Committee, National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS). D. E. was supported by JSPS KAKENHI grant No. JP 17K14254.