...survey

Based on observations made with the Isaac Newton Telescope (INT) and the Jacobus Kaptein Telescope (JKT) operated on the island of La Palma by the Isaac Newton Group at the Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias; and on observations made with the Nordic Optical Telescope (NOT) at the same observatory.

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...survey

Figure 5 is only available at the http://www.edpsciences.com

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...Martín^1,

Present address: Astronomy Department, University of California, Berkeley, CA 94720, U.S.A.

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...Magazzù^3,

Also at: Obsservatorio Astrofisico di Catania, Città Universitaria, Viale Andrea Doria 6, I-95125 Catania, Italy.

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...IRAF

IRAF is distributed by National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.

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