LIGHTS: A novel technique to characterize galaxy edges. A closer look at NGC3486

For the first time, the LIGHTS survey is routinely imaging galaxies at a depth and spatial resolution comparable to what LSST will produce in 10 years (i.e. 31 mag/arcsec^2). This opens up the possibility of probing the edge of galaxies with a precision that we have been unable to achieve in the past. Traditionally, galaxy borders have been analyzed in one-dimension through ellipse averaging or visual inspection. Our approach allows for a two-dimensional exploration of galaxy edges, which is crucial for understanding deviations from disk symmetry and the environmental effects on galaxy growth. In this paper, we propose a novel method using the second derivative of the surface mass density profile of a galaxy to determine its edges. Our technique incorporates Wiener deconvolution to effectively remove the effect of the Point Spread Function (PSF) by the galaxy itself. This offers a robust alternative to traditional edge-detection methods. These techniques will be of paramount importance for future ultra-deep surveys such as LSST, Euclid and Roman, providing a new standard for precision in galactic edge detection.