...$Z = Z_\odot/20$)

$12+\log~({\rm O/H})_{\odot} = 8.92$(Anders & Grevesse 1989).

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... Peak

Kitt Peak National Observatory (KPNO) is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation (NSF).

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... Alto

German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institute for Astronomy, Heidelberg, jointly with the Spanish National Commission for Astronomy.

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... IRAF

IRAF is the Image Reduction and Analysis Facility distributed by the National Optical Astronomy Observatory, which is operated by the AURA under cooperative agreement with the NSF.

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... MIDAS

Munich Image Data Analysis System, provided by the European Southern Observatory (ESO).

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... (STScI)

STScI is operated by the AURA, Inc., under NASA contract NAS5-26555.

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