Changing Ionization Conditions in SDSS Galaxies with Active Galactic Nuclei as a Function of Environment from Pairs to Clusters
Abstract
We study how active galactic nucleus (AGN) activity changes across environments from galaxy pairs to clusters using 143,843 galaxies with z < 0.2 from the Sloan Digital Sky Survey. Using a refined technique, we apply a continuous measure of AGN activity, characteristic of the ionization state of the narrow-line emitting gas. Changes in key emission-line ratios ([N II] λ6548/Hα, [O III] λ5007/Hβ) between different samples allow us to disentangle different environmental effects while removing contamination. We confirm that galaxy interactions enhance AGN activity. However, conditions in the central regions of clusters are inhospitable for AGN activity even if galaxies are in pairs. These results can be explained through models of gas dynamics in which pair interactions stimulate the transfer of gas to the nucleus and clusters suppress gas availability for accretion onto the central black hole.
Additional Information
© 2014 American Astronomical Society. Received 2014 June 15; accepted 2014 September 2; published 2014 October 14. We thank the anonymous referee for constructive comments. We also thank Surhud More, Steve Bickerton, Claire Lackner, Brian Feldstein, Josh Speagle, and Lisa Kewley for helpful discussions. In addition, E.T.K. is particularly grateful to Richard Ellis for guidance throughout the research project and during the writing process. E.T.K. warmly thanks C.L.S. and J.D.S. for their invaluable mentoring, as well as S.L.E., J.T.M., and D.R.P. for their support. Furthermore, the Kavli Institute for the Physics and Mathematics of the Universe and the California Institute of Technology with its Summer Undergraduate Research Fellowships (SURF) program provided key financial and organizational assistance.Attached Files
Published - 0004-637X_795_1_62.pdf
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Additional details
- Eprint ID
- 52218
- Resolver ID
- CaltechAUTHORS:20141201-104635573
- Kavli Institute for the Physics and Mathematics of the Universe
- Caltech Summer Undergraduate Research Fellowship (SURF)
- Created
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2014-12-01Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field