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Please use this identifier to cite or link to this item: http://hdl.handle.net/10481/28377

Title: Molecular gas around low-luminosity AGN in late-type spirals
Authors: Böker, Torsten
Schinnerer, Eva
Lisenfeld, Ute
Issue Date: 2011
Abstract: We have studied the molecular gas in the vicinity of low-luminosity active galactic nuclei (AGNs) in three bulge-less spiral galaxies: NGC 1042, NGC 4178, and NGC 4395. The (1−0) and (2−1) transitions of gaseous carbon monoxide (CO) are clearly detected within the central kpc of all three galaxies. In the case of NGC 4395, this constitutes the first reported detection of CO. In general, the CO emission is faint, as may be expected from their less-than-spectacular star formation activity. Interestingly, however, both face-on galaxies in our sample (which allow an unimpeded view of their nucleus) show an elevated intensity ratio CO(2−1)/CO(1−0) when compared to similar late-type spirals without an AGN. We discuss that this is unlikely due to a very compact CO source. Instead, we speculate that even energetically weak AGN can impact the physical state of the surrounding gas. We do not detect any tracers of dense molecular gas such as HCN or HCO+, but the sensitivity of our observations allows us to establish upper limits that lie at the low end of the range observed in more energetic AGN. The derived gas density is less than nH2 ≈ 2 × 103 cm-3 which is significantly lower than in most other nearby galaxies. The scarcity of dense gas suggests that the conditions for star formation are poor in these nuclei.
Sponsorship: Support by the research project AYA2007- 67625-C02-02 from the Spanish Ministerio de Ciencia y Educación and the Junta de Andalucía (Spain) grant FQM-0108.
Publisher: European Southern Observatory (ESO); Springer Verlag
Keywords: ISM
Molecules
Galaxies
Spiral
Nuclei
URI: http://hdl.handle.net/10481/28377
ISSN: 0004-6361
1432-0746
Rights : Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License
Citation: Böker, T.; Schinnerer, E.; Lisenfeld, U. Molecular gas around low-luminosity AGN in late-type spirals. Astronomy and Astrophysics, 534: A12 (2011). [http://hdl.handle.net/10481/28377]
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