Optimal strategies for surveys with WSO-UV/ISSIS

Abstract

Astronomical surveys provide an amazing amount of information for the understanding of specific astrophysical problems, from the large scale structure of galaxy clusters, to the formation of stars. Large scale surveys are often complemented with smaller surveys based on many pointings in areas of special interest. The World Space Observatory-Ultraviolet (WSO-UV) is the coming 2-m class facility for UV astronomy. The imaging instrument in WSO-UV is ISSIS (Imaging and Slitless Spectroscopy Instrument). A fraction of the ISSIS science will involve mapping and analyzing areas of the sky extending many arc minutes to observe clusters of galaxies, stellar associations, star-forming regions (either galactic or extragalactic) and other interesting astronomical objects. ISSIS field of view is small (<2 arcmin) and survey strategies need to be defined, well in advance, to optimize the scientific output. We present the analysis done by our team to define optimal strategies for mapping large areas of the sky where relevant sources may be scattered in a non-random manner. The optimization problem is addressed with different mathematical programming models: Continuous, Binary and Sample-Binary Mathematical Programming Models, as well as through heuristic approaches. A set of optimization algorithms is defined for various surveying strategies based on mathematical approaches.