People involved at OAB: Parmeggiani
Parmeggiani, in collaboration with E. Diolaiti (Post Doc, University of Padova), improved their original code StarFinder.
The StarFinder code has been designed for the photometric and astrometric analysis of crowded stellar fields. It has been applied to high and low resolution images, obtained by different techniques (Adaptive Optics, HST, seeing-limited ground-based observations).
The current version of the code assumes a uniform Point Spread Function (PSF) across the field. Some preliminary tests on wide field seeing-limited observations have been performed, partitioning the image into sub-regions and extracting a PSF for each sub-frame. This approach has proven to be not very satisfactory, showing that a better modelling of the continuous variation of the PSF across the image is certainly required. Other tests have been performed, trying to reproduce the PSF at any field location by degrading the on-axis response with a semi-empirical model, calibrated on several field stars. All the above reported tests are somewhat preliminary and the implementation of a robust though flexible technique to handle a spatially varying PSF is now a major development issue of the code.
StarFinder has been specifically designed for images characterized by complicated and highly structured PSF. Also due to this approach, it is able to detect the stellar sources with high reliability, even in a crowded environment. An interesting development related to this feature is the classification of stellar and non-stellar sources in a mixed field. Exploiting the image matching methods currently implemented in the code, it might be possible to accomplish this task with high reliability. While a complete object classification is beyond the current plans, this extension of the program should be intended as a way to recognize the point-like sources in a mixed field image, thus allowing a better detection of the extended objects.