PSF homogenization for multi-band photometry from space on extended objects

Abstract : We present a fast and robust tool to create PSF matching kernels for multi-band photometric studies. Such kernels are useful for convolving images down to the same PSF prior to computing flux measurements like aperture photometry or spectral fitting. Unlike similar existing methods, we use a Wiener filter to take into account the real shape of the effective PSF, usually very complex for space telescopes. We apply this scheme to Euclid simulated PSF images to demonstrate the efficiency of the algorithm.