Table of Contents

Introduction

Definition of the survey

Observations

Photometric properties

Obtaining survey data

In recent years considerable progress has been made in understanding the distribution and evolution of galaxies. Much of this has been driven by the advent of large redshift surveys, such as the CFA2 and SSRS2 surveys which cover a third of the sky and contain over 14,000 galaxy redshifts. These surveys reach mean redshifts of z ~ 0.0025 and reveal structures with sizes as large as 50 Mpc. Multi-object spectrographs, using either slits or optical fibres, have now provided large redshift samples over smaller areas of sky. For example, the Los Campanas Redshift Survey contains 26,418 redshifts, with a mean of z ~ 0.1, and extends over 700 square degrees of sky. The deepest current surveys, such as the Canada-France Redshift Survey, reach z ~ 0.5 and contain several thousand objects.

The survey observations are conducted using the 3-meter liquid-mirror telescope of the NASA Orbital Debris Observatory. Two detectors have been used for survey observations. The first was a 2048 x 2048 pixel Loral CCD. It was a thick, front-illuminated device, with reasonable response at red and near-infrared wavelengths but limited blue response. The pixel size was 15 microns square, which gave an image scale of 0.598 arcsec/pixel. This detector failed in 1998, after two years of survey obervations. It was replaced in 1999 by a 1024 x 1024 pixel SITe CCD. This new CCD is thinned and back-illuminated, which results in a higher quantum efficiency and much better blue response. The 24 micron pixel size corresponds to 0.957 arcsec.

At the start of each night, a filter is placed in front of the CCD camera. These are selected from UBC's set of 40 intermediate-bandwidth interference filters. The filters have central wavelengths at a uniform logarithmic spacing of 0.01 and constant bandwidth of 0.02 in log wavelength. Because of the declining sensitivity of the CCD at long and short wavelengths, only 33 filters are used in the survey which cover the range 455 - 948 nm.

Observations have been conducted during the months of April-June since 1996. In 60 nights we have so far obtained data through 16 intermediate-bandwidth filters. Table 2 provides a summary of the bands observed to date, the number of nights, detector, and the ranges of right ascension.

The survey detects objects to a typical magnitude of m(AB) = 20.4, and to a surface brightness limit of u(AB) = 23.5. The photometric accuracy ranges from 0.02 mag. for the brighter objects to 0.2 mag. for the faintest. For each object we determine the positions, major and minor axis size, position angle, and magnitudes at each observed wavelength. Our preliminary catalogue lists data for over 500,000 objects.