OPERA:: Objective-prism reduction package

Surveys of star-forming galaxies are of vital importance to constrain galactic evolution theories. One of the most successful searching methods is the objective-prism (OP) technique, which can register thousands of low resolution spectra in large areas. The UCM-CIDA (Universidad Complutense de Madrid-Centro de Investigacion F. J. Duarte) project expects to cover 150 square degrees and detect similar to 2000 H alpha: emission line galaxies. OPERA (Objective Prism Enhanced Reduction Algorithms) is an automatic method to handle and analyze such amount of data. It goes trough the detection of the objects in the image, extraction of one-dimensional spectra and identification of the emission line feature. The main advantages of a method of this kind are: 1) to avoid subjectivity inherent to visual inspection used in past studies; and 2) the ability to obtain physical parameters without follow-up spectroscopy.