Archimedean aspects of Siegel modular forms of degree 2

Abstract

We survey the archimedean representations and Langlands parameters corresponding to holomorphic Siegel modular forms of degree~$2$. This leads to a determination of archimedean local factors for various $L$-functions and all vector-valued weights. We determine the Hodge structures that correspond to holomorphic Siegel modular forms and clarify the relationship with four-dimensional symplectic artin representations.