Metallicity gradients at large galactocentric radii using the near-infrared Calcium triplet
Abstract
We describe a new spectroscopic technique for measuring radial metallicity gradients out to large galactocentric radii. We use the DEep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck telescope and the galaxy spectrum extraction technique of Proctor et al. We also make use of the metallicity sensitive near-infrared Calcium II triplet (CaT) features together with single stellar population models to obtain metallicities. Our technique is applied as a pilot study to a sample of three relatively nearby (≤30 Mpc) intermediate-mass to massive early-type galaxies. Results are compared with previous literature inner region values and generally show good agreement. We also include a comparison with profiles from dissipational disc–disc major merger simulations. Based on our new extended metallicity gradients combined with other observational evidence and theoretical predictions, we discuss possible formation scenarios for the galaxies in our sample. The limitations of our new technique are also discussed.
Additional Information
© 2009 The Authors. Journal compilation © 2009 RAS. Accepted 2009 August 25. Received 2009 August 25; in original form 2009 March 5. We thank the anonymous referee for his/her careful reading and for offering very useful and constructive comments. We also thank G. Hau, L. Spitler, T. Mendel, J. Strader and A. Romanowsky for useful discussions and comments. CF thanks the Anglo-Australian Observatory for financial support in the form of a graduate top-up scholarship. RNP and DAF thank the ARC for financial support. Support for PFH was provided by the Miller Institute for Basic Research in Science, University of California Berkeley. This material is based upon work supported by the National Science Foundation under Grant AST-0507729. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The analysis pipeline used to reduce the DEIMOS data was developed at UC Berkeley with support from NSF grant AST-0071048. We acknowledge the usage of the HyperLeda data base (http://leda.univ-lyon1.fr) and of NASA/IPAC Extragalactic Data base (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.Attached Files
Published - mnras0400-2135.pdf
Accepted Version - 0908.3705.pdf
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Additional details
- Eprint ID
- 103622
- Resolver ID
- CaltechAUTHORS:20200601-143025513
- Anglo-Australian Observatory
- Australian Research Council
- Miller Institute for Basic Research in Science
- AST-0507729
- NSF
- W. M. Keck Foundation
- AST-0071048
- NSF
- NASA/JPL/Caltech
- Created
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2020-06-01Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field