Presentation 1 : None
poster :relative performances of for photometric packages working on very crowded stellar fields.field
R. Dubout-Crillon, A. Llebaria
We assess the relative performances of the softwares DAOPHOT, DAOPHOT/
ALLSTAR, CAPELLA, SEXTRACTOR for stellar fields with irregular
backgrounds and asymmetric PSFs. The first three packages use PSF fit-
tings, the fourth performs fixed aperture photometry and a small aperture
was used in order to minimize the contaminating fluxes.
A typical extragalactic stellar field has been used to built synthetic
counterparts in order to test the photometric accuracy with respect to
the blend extent. The results show in which cases DAOPHOT, DAOPHOT/
ALLSTAR and SEXTRACTOR overestimate the fluxes of blended stars.
SEXTRACTOR results dispersions are near the ALLSTAR ones, but as we can
expect, systematic overestimation appears for the severely blended
stars. For stars merged in the wings of brighter stars, CAPELLA reaches
the best accuracy. For isolated and moderately blended stars, ALLSTAR,
CAPELLA and SEXTRACTOR results are near.