The APOGEE Library of Infrared SSP Templates (A-LIST): High-Resolution Simple Stellar Population Spectral Models in the H-Band

Integrated light spectroscopy from galaxies is used to study stellar populations that cannot be resolved into individual stars. These analyses often rely on stellar population synthesis (SPS) techniques. However, the spectral templates available for SPS methods are limited, especially in the near-infrared. We present A-LIST (APOGEE Library of Infrared SSP Templates), a new set of high-resolution, near-IR SSP spectral templates spanning a wide range of ages (2-12 Gyr), metallicities (−2.2 < [M/H] < +0.4) and alpha-element abundances (−0.2 < [alpha/M] < +0.4). This set of SSP templates is the highest resolution (R~22500) available in the near-IR, and the first such based on an empirical stellar library. Our models are generated using spectra of roughly 300,000 stars from APOGEE spread across the Milky Way, with a wide range of metallicities and abundances. We show that our model spectra provide accurate fits to APOGEE spectra of M31 globular clusters, with best-fit metallicities agreeing with those of previous estimates to within ~0.1 dex. We also compare these model spectra to lower-resolution E-MILES models and demonstrate that we recover the ages of these models to within ~1 Gyr. This library is publicly available.