RemoveYoung: A tool for the removal of the young stellar component in galaxies within an adjustable age cutoff

The optical morphology of galaxies holds the cumulative record of their assembly history, and techniques for its quantitative characterization offer a promising avenue toward understanding galaxy formation and evolution. However, the morphology of star-forming galaxies is generally dictated by the youngest stellar component, which can readily overshine faint structural/morphological features in the older underlying stellar background (e.g., relics from recent minor mergers) that could hold important insights into the galaxy build-up process. Stripping off galaxy images from the emission from stellar populations younger than an adjustable age cutoff tcut can, therefore, provide a valuable tool in extragalactic research. RemoveYoung (RY), a publicly available tool that is presented here, exploits the combined power of integral field spectroscopy (IFS) and spectral population synthesis (SPS) toward this goal. Two-dimensional (2D) post-processing of SPS models to IFS data cubes with RY permits computation of the spectral energy, surface brightness, and stellar surface density distribution of stellar populations older than a user-defined tcut. This suggests a variety of applications of star-forming galaxies, such as interacting or merging galaxy pairs and lower mass starburst galaxies near and far; these include blue compact and tidal dwarf galaxies.