The GEFE team of collaborators, is formed by scientists from several countries. This is a project which has been awarded the CCI's 5 international time project at the telescopes in Roque de los Muchachos, La Palma, Canary Islands from October 1991 to December 1992: a) The 4.2m William Herschel Telescope (WHT), b) The 2.5m Isaac Newton Telescope (INT), c) The 2.5m Nordic Optical Telescope (NOT), and d) The 1m Jacobus Kapteyn Telescope (JKT). Our research project aims to determine the parameters that control the magnitude and efficiency of stellar bursts in stellar systems. This is based on two assumptions, namely that the strength of a burst is defined by the local properties of the star forming cloud and, secondly, that to unveil such properties one has to study in great detail the physical properties of the gas within the volume ionized by the massive members of the newly formed cluster. Thus, estimates of the stellar mass and stellar content in several regions of recent star formation, as well as a variety of measurements revealing the local physical properties (density, metal content, gas to dust ratio, temperature, mass, etc.) of the star forming clouds are envisaged. To fulfill the aims of our project we have selected a sample of giant HII regions in nearby spiral galaxies and HII galaxies. Knowledge of the parameters that control the strength of a burst will clearly have a direct impact on many aspects of star formation, particularly on the history of star formation and the chemical evolution of galaxies, and on the early stages of galaxy formation.
The imaging part of this project has obtained 340 CCD frames for 14 nearby spiral and irregular galaxies and 160 frames for 42 HII galaxies using B,V,R and I broad band and H narrow band at both the prime focus at the 2.5 m Isaac Newton telescope and the 1m Jacobus Kapteyn telescope at La Palma. I have been directly co-responsible for this imaging part of the project and have dealt closely with the data reduction and analysis. We will still pursue the line of work of surface photometry analysis to achieve the goals briefly commented below.