The Fornax Spectroscopic Survey — Low Surface Brightness Galaxies in Fornax

Abstract

AbstractThe Fornax Spectroscopic Survey is a large optical spectroscopic survey of all 14 000 objects with 16.5 < BJ < 19.7 in a 12 deg2 area of sky centered on the Fornax Cluster. We are using the 400-fibre Two Degree Field spectrograph on the Anglo-Australian Telescope: the multiplex advantage of this system allows us to observe objects conventionally classified as “stars” as well as “galaxies”. This is the only way to minimise selection effects caused by image classification or assessing cluster membership.In this paper we present the first measurements of low surface brightness (LSB) galaxies we have detected both in the Fornax Cluster and among the background field galaxies. The new cluster members include some very low luminosity (MB ≈ −11.5 mag) dwarf ellipticals, whereas the background LSB galaxies are luminous (−19.6 < MB < −17.0 mag) disk-like galaxies.