Are 1-D techniques more robust against neighboring contamination than 2-D fitting techniques?
Why are the fit parameters so sensitive to the sky value and/or the presence of neighboring galaxies? This is a well known issue in the galaxy fitting business that one should be very cautious about. Galaxy profiles can decline very slowly out at large radius. In fact, for normal galaxies, the more centrally concentrated a galaxy is, i.e. large Sérsic index n, the more slowly the outer galaxy wing tends to decline (sounds paradoxical, but it’s true). Because of this dual behavior, having elevated flux in the outskirts due to contaminating sources (i.e. galaxies, flatfield errors, etc.) can sometimes lead to a higher than normal Sérsic index n. For this reason it is important to be aware of the flux profile in the wings, and also to get the sky value right. If a profile already has a high intrinsic Sérsic index (n > 2), a small error in the background sky can drive the index up even higher, leading to large systematic errors in the magnitude and size. This means that a de Vaucouleurs pr
