CORE VELOCITY DISPERSIONS AND METALLICITIES OF 3 GLOBULAR-CLUSTERS BELONGING TO THE FORNAX DWARF SPHEROIDAL GALAXY

Integrated light spectra, obtained at the European Southern Observatory (ESO) at La Silla, Chile, of the three brightest globular clusters of the Fornax dwarf spheroidal galaxy, allow determination, by cross-correlation techniques, of the projected core velocity dispersions, with values sigma(p)(core) = 8.8(+1.0, -1.1), 5.1(+1.0, -1.2), and 7.0(+1.1, -1.3) km s-1 for the clusters 3, 4, and 5, respectively. The corresponding estimates of the mass-to-light ratios, viz. M/L(V) = 3.2 +/- 0.8, 1.7 +/- 0.8, and 5.2 +/- 1.9(M/L(V))., are similar to the typical M/L(V) values obtained for Galactic globular clusters. From the point of view of theories of cluster formation and evolution, such a similarity is worth noticing, given the fact that the present-day environments of globular clusters in the Galaxy and in the Fornax dwarf spheroidal galaxy appear so different. From the total area of the cross-correlation function of the integrated light spectra, metallicity estimates can be derived with an accuracy of 0. 15 dex. We obtain values of [Fe/H] equal to -1.93, -1.35, and -1.89 for the Fornax clusters 3, 4, and 5, respectively. These results, in excellent agreement with earlier determinations, confirm the existence of a large metallicity range among the Fornax globular clusters and strengthen the evidence that Fornax has a rather complex history of star and cluster formation, unexpected for such a low-mass galaxy.