Testing the Extremes of IMF Variability with New Stellar Population Models

摘要

The advancement of infrared (IR) detectors opened a range of observational probes of galaxy physics. One of the most important advancements in recent years is the measurement of a variable IMF in certain high-mass, high-metallicity systems. However, the models used to make IMF measurements lagged in their ability to probe low-mass, low-metallicity systems which has hindered our ability to discern the cause of these variations. In this work we use a new suite of stellar population synthesis (SPS) models to probe the IMF in low-mass systems over a much wider range of metallicity than in previous studies. We compare our results to massive early-type galaxies (ETGs) and available dynamical measurements. Variation among the sample in this paper is only~50% in normalized M/L compared to the~4x among the ETG sample. This suggests that metallicity is not the sole driver of IMF variability and additional parameters need to be considered.