The counterparts of Local Group dwarf spheroidals in nearby clusters

Abstract

In this contribution, we report on the discovery of dwarf spheroidals (dSphs) in the core of the Fornax cluster. Their photometric properties -- like magnitude, colour, surface brightness -- are very similar to those of Local Group dSphs. However, at a given total magnitude, dSphs in Fornax seem to be more extended than their Local Group counterparts. The membership of several dwarf galaxy candidates in Fornax has been confirmed by surface brightness fluctuation measurements on deep wide-field images taken with the Magellan telescope. The analysis of these images also confirms the flat faint end slope of the luminosity function for dSphs in Fornax which contradicts the expected large number of small dark matter halos connected to dwarf galaxies in LambdaCDM theory. Dwarf spheroidals have also been detected in the Hydra I and Centaurus cluster. A preliminary analysis of their photometric properties shows that they obey similar scaling relations as their counterparts in Fornax and the Local Group.