The globular clusters of dwarf spheroidal galaxies

The possibility that the Sagittarius dwarf spheroidal might have formed as a Searle-Zinn fragment in the outer halo of the Galaxy is discussed. Argume nts in favor of this hypothesis are (1) the luminosity distribution of glob ular clusters in both Sagittarius and in the outer halo (R-gc > 80 kpc) app ear to be bimodal with peaks near M-upsilon similar to -5 and -10, and (2) the globular clusters in both Sgr and the outer halo have a significantly l arger age spread than do the globulars in the inner halo of the Galaxy. How ever, a counterargument is that only one of the four globulars associated w ith Sgr has the large half-light diameter that is diagnostic of outer halo clusters. The absence of globular clusters from all Local Group dwarf spher oidal galaxies fainter than M-upsilon = -12 shows that their specific globu lar cluster frequency must be lower than it is in the Fornax dwarf spheroid al. This result suggests that Fornax may have had an unusual evolutionary h istory.