The metallicity gradient and distribution function of globular clusters around NGC 1399

Abstract

Four fields in the elliptical galaxy NGC 1399 in the Fornax cluster have been examined by Washington CCD photometry. The application of color-magnitude diagrams and color-color diagrams discloses a large population of globular clusters, as well as a field population that becomes increasingly important at larger radii and fainter than T(1) of about 21.5. A small gradient in the mean color with radius translates into a metallicity difference of approximately 0.2 dex over a radial extent of approximately 3 arcmin. The metallicity distribution function of the NGC 1399 is investigated in order to derive the Fe abundances on the Zinn scale. The abundances are precise to approximately 0.25 dex and accurate to approximately 0.3 dex. A nuclear abundance for NGC 1399 of +0.14 +/- 0.2 is also determined.