Submitted by Atul DEEP
A. Deep, G. Fiorentino, L. Jolissaint, E. Tolstoy
Leiden Observatory; Kapteyn Astronomical Institute (University of Groningen)
The full scientific exploitation of AO images to study resolved stellar populations is still in a nascent stage. This requires pushing to the faint limits and carrying out deep and accurate crowded field photometry and astrometry. The main complexity of AO images is that the correction is never perfect and the PSF always has a complex residual halo around the central core which contains a large fraction of the light. The variations in seeing over short periods of time and anisoplanatism effects create strongly time dependent effects in the PSF. We use the analytic AO modeling tool PAOLA to simulate a range PSFs. The theoretical variations of PSF for different field angles and atmospheric conditions are examined, and then compared with the PSFs obtained with Monte Carlo simulation tool like OCTOPUS and also with real data from MAD. The analytic functions derived from PAOLA can in principle be used as an input to photometric codes likes DOPHOT and STARFINDER to improve the results. It can also investigate choices for first-order parameters such as the number of deformable mirrors, sub-apertures, actuators etc that may be required to optimise the instrument with these science goals in mind. This study provides useful insights into the performance capabilities of future instruments such as, for example, MICADO on the ELT.