Redshift-dependent Initial Mass Function: Impact on High Redshift Obeservations

Stellar population synthesis (SPS) is a common technique used for creating model spectra of stellar populations. A critical component of SPS is the initial mass function (IMF), which describes the distribution of stellar masses formed during a star formation event. In this project, we explore how a redshift-dependent IMF affects the luminosity and shape of a synthetic stellar population spectrum. A common way to incorporate redshift dependence is to use a redshift dependent critical mass which increases at higher redshift. Thus, at higher redshift, more high-mass stars are formed and the stellar populations are more luminous and bluer at young ages. They become less luminous at higher ages. We use Flexible Stellar Population Synthesis (FSPS) to generate these spectra for use in cosmological simulations, and we will explore how the increased ionizing radiation generated by these luminous and blue stellar populations can change our understanding of high-redshift galaxy observations.