Astron. Astrophys. 355, 900-914 (2000)

6. Summary

In this paper we have presented an overview of the FSS, the first complete, all-object spectroscopic survey to cover a large area of sky. This project has only been made possible by the advent of the 400-fibre Two-degree Field spectrograph on the Anglo-Australian Telescope. In total we hope to observe some 14,000 objects to a magnitude limit of =19.7 - both `stars' and `galaxies' - in a 12 square degree area of sky centred on the Fornax Cluster.

The main technical challenges of the project concern the preparation of the target catalogue and the analysis of the resulting spectra. Our input catalogues are based on UK Schmidt Sky Survey plates digitised by the APM facility. We have demonstrated that the APM image catalogues provide sufficiently accurate target positions and photometry for the unresolved sources. For the resolved sources our photometry is derived by fitting exponential profiles to the image parameters measured by the APM. We have tested our calibration with new CCD observations. We use a semi-automated procedure to classify our spectra and measure radial velocities based on cross-correlation comparison with a set of stellar spectra, two emission-line galaxy spectra and one QSO spectrum. This procedure successfully identifies stars, galaxies and QSOs completely independently of their image morphology.

When the FSS is complete we will have a unique, complete, sample of Galactic stars, Fornax Cluster galaxies, field galaxies and distant AGN. We have discussed some of the scientific questions that can be addressed with such a sample. The principal objective is to obtain an unbiased sample of cluster members, which includes compact galaxies and low surface brightness dwarfs, independent of a membership classification based on morphological appearance.

Redshift/velocity distributions are presented here based on spectroscopic results from the first of four 2dF fields. The velocity distribution of Galactic stars can be understood in terms of a conventional three-component model of the Galaxy. The Fornax Cluster dwarf galaxies in the first 2dF field have a mean heliocentric radial velocity of and a radial velocity dispersion of . The Fornax Cluster is well-defined dynamically, with a low density of galaxies in the foreground and immediate background. Beyond , the large-scale structure behind the Fornax Cluster is clearly delineated out to a redshift . The compact galaxies found behind the cluster by Drinkwater et al. (1999a) are found to follow the structures delineated by the general galaxy population, as are background low surface brightness galaxies. Some more detailed initial results have already been presented elsewhere (Drinkwater et al. 1999a, 1999b).

© European Southern Observatory (ESO) 2000

Online publication: March 21, 2000
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