A search for active star-forming galaxies with the ESO 1 meter Schmidt telescope
Résumé
A new search for active galaxies has been conducted using the ESO 1 meter Schmidt telescope, in order to build a sample of emission lines and ultraviolet excess objects. The observational strategy was focussed on getting deeper detection and better completeness on faint apparent magnitude objects than those obtained in preceding surveys. The reduction procedure aims at a maximum astrophysical output before any complementary follow-up, thus we expect an easy selection of interesting targets from the catalog of candidate galaxies (to be published later) when future observations will be planned. The redshifts are measured on Schmidt objective prism plates with a mean accuracy of 160 km/s. This accuracy has been checked by means of published velocitites up to 5000 km/s, but the emission line galaxies detected have redshifts up to z = 0.06. The R magnitudes, (U-R) colors, isophotal diameters, surface brightnesses and quantitative morphological parameters are derived from U/R bicolor direct plates. Colors are tied to the U, R Basel system by means of a statistical comparison of the field star instrumental color distribution with the field star Basel color distribution at a symmetric Galactic latitude. The accuracy of the (U-R)_Basel zero point is at best 0.10 magnitude. The asymptotic R magnitudes are calibrated in Cousins system with ESO-LV small diameter galaxies, and are thought to be accurate to 0.30 magnitude. The expected limiting R magnitude of the survey is 18.5. The present paper is limited to a description of the methodology, illustrated with preliminary results obtained in two fields.
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