Stellar populations of extragalactic globular clusters

Globular clusters (GCs) are the oldest (ages up to 13.6 Gyr), but not the most metal-poor ( -2.9<[Fe/H]<0 dex) objects in the Universe. Studying properties of their stellar populations and comparing them with the properties of structural components of galaxies and stellar streams is necessary to understand the processes of nucleosynthesis and galaxy formation. We analyse integrated-light (IL) spectra of extragalactic GCs in order to determine the properties of their horizontal branch stars, ages and chemical composition. For this purpose, we compare the observed and synthetic spectra of clusters calculated using stellar atmosphere models. In this paper, we address the questions: 1) what signatures of multiple stellar populations can be inferred from the analysis of IL low-resolution spectra of GCs; and 2) what the origin of GCs is and their multiple stellar populations. For the second question, we consider only two sources of multiple stellar populations: asymptotic giant branch and rapidly rotating massive stars, and briefly consider the problems in this scientific area.