Astron. Astrophys. 327, 503-512
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Halo and bulge/disk globular clusters in the S0 galaxy NGC 1380*
Markus Kissler-Patig1,2, Tom Richtler1, Jesper Storm3, and Massimo Della Valle4
1Sternwarte der Universität Bonn, Auf dem Hügel 71, D-53121 Bonn,
Received 29 May 1997 / Accepted 30 June 1997
We investigated the globular cluster system of the S0 galaxy NGC 1380 in the Fornax cluster with deep BVR photometry. We identified two, presumably old, populations of globular clusters. The blue globular clusters seem to be counterparts to the halo globular clusters in our Milky Way. They have comparable colors and magnitudes, are spherically distributed around the elliptical galaxy but have a very flat surface density profile. The red population follows the stellar light in ellipticity and position angle, has a similar magnitude distribution to the blue clusters, and a surface density profile comparable to that of globular clusters in other Fornax ellipticals. From their colors the red clusters appear slightly more metal rich then the metal rich globular clusters in the Milky way. We associate this red population with the bulge and disk of NGC 1380. While these two populations are compatible with a merger formation, we unfortunately see no hint in favor nor against a past merger event in the galaxy.
This would be the first identification of halo and bulge globular clusters in an early-type galaxy by their colors and spatial distribution, and could hint to the presence of halo and bulge globular clusters in all galaxies.
The globular cluster luminosity functions in the three colors will be discussed in detail in a separate paper together with the implications of the absolute magnitude of SN 1992A.
Key words: galaxies: NGC 1380; elliptical and lenticular; star clusters
*Based on data collected at the European Southern Observatory,
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© European Southern Observatory (ESO) 1997
Online publication: October 14, 1997