Globular cluster systems of early-type galaxies in Fornax *
M. Kissler-Patig 1, 2,
S. Kohle 2,
M. Hilker 2,
T. Richtler 2,
L. Infante 3 and
H. Quintana 3
Received 20 May 1996 / Accepted 5 August 1996
We studied through V and I photometry the properties of the globular cluster systems of five early-type galaxies in the Fornax galaxy cluster: NGC 1374, NGC 1379, NGC 1387, NGC 1427, and the central giant elliptical NGC 1399. While the four normal galaxies have between 300 and 500 globular clusters, leading to specific frequencies of for all of them, NGC 1399 has around globular clusters and a specific frequency of .
The globular cluster colors are somewhat redder than those of the Milky Way globular clusters, however with a similar dispersion. This indicates a wide range of metallicities in all our galaxies with a mean metallicity somewhat higher than in the galactic halo, comparable to the galactic bulge. In NGC 1399 the dispersion is about twice as high, and the color distribution could be multi-modal. No color gradient could be detected within the sensitivity of our photometry.
The density profiles of the globular cluster systems follow the galaxy light in all the galaxies. In NGC 1399 the globular cluster system is much flatter than in the other galaxies, but coincides with the large cD envelope of the galaxy. None of the globular cluster systems is clearly elongated, even the ones in NGC 1374 and NGC 1427 (E1 and E3 respectively) appear rather spherical.
From a comparison with studied globular cluster systems in spiral galaxies, we conclude that our faint ellipticals have no more globular clusters than spirals of the same mass, and neither differ in their other properties, such as globular cluster colors and morphological properties of the system. For these galaxies there is no need to imply a different formation scenario of the globular cluster system. The central giant elliptical has far more globular clusters and shows signatures of a different history in the building up of its globular cluster system.
Key words: galaxies: clusters: individual: Fornax galaxies: elliptical galaxies star clusters globular clusters: general
Send offprint requests to: M. Kissler-Patig (Bonn)
© European Southern Observatory (ESO) 1997
Online publication: July 3, 1998