Inter-cluster Filaments of Galaxies Programme: Pilot Study Survey and Results

Abstract

We present results from a pilot study of a new wide-field, multicolour (BVR) CCD imaging project, designed to examine galaxy evolution along large scale filaments that connect clusters of galaxies at intermediate redshifts (0.08 < z < 0.20). Our pilot dataset is based on 0.56 square degrees of observations targeted on Abell 1079 and Abell 1084 using the Wide Field Imager on the Anglo-Australian Telescope. We describe our data reduction pipeline and show that our photometric error is 0.04 mags. By selecting galaxies that lie on the colour-magnitude relation of the two clusters we verify the existence of a low density (approx 3-4 square Mpc) filament population conjoining them at a distance of > 3 r_{Abell} from either cluster. By applying a simple field correction, we characterize this filament population by examining their colour distribution on a (V-R)-(B-V) plane. We confirm the galaxian filament detection at a 7.5 sigma level using a cut at M_V=-18 and we discuss their broad properties.

9 pages. 9 figures. Accepted for publication in MNRAS