A Simple Spectroscopic Technique to Identify Rejuvenating Galaxies

Abstract Rejuvenating galaxies are unusual that fully quench and then subsequently experience a “rejuvenation” event to become star-forming once more. Rejuvenation rates vary substantially in models of galaxy formation: 10%–70% massive expected rejuvenation by z = 0. Measuring the rate is therefore important for calibrating strength star-formation feedback mechanisms. However, these observations challenging because rejuvenating systems blend with normal broadband photometry. In this paper, we use spectral energy distribution-fitting code Prospector search observational markers distinguish from galaxies. We find have smaller Balmer absorption line equivalent widths (EWs) than This analogous well-known “K+A” or post-starburst galaxies, which strong due A-stars dominating light: case, lack A-stars, instead resembling “O—A” systems. H β , γ and/or δ EWs ≲3 Å corresponds highly pure selection Interestingly, while technique effective at identifying mild rejuvenation, “strongly” remain nearly indistinguishable stellar outshining effect. conclude measuring populations an efficient method identify populations, discuss several techniques either remove resolve nebular emission typically lies on top lines.