Taylor coefficients of non-holomorphic Jacobi forms and applications

In this paper, we prove modularity results of Taylor coefficients of certain non-holomorphic Jacobi forms. It is well known that Taylor coefficients of holomorphic Jacobi forms are quasimodular forms. However, recently there has been a wide interest in Taylor coefficients of non-holomorphic Jacobi forms, for example, arising in combinatorics. In this paper, we show that such coefficients still inherit modular properties. We then work out the precise spaces in which these coefficients lie for two examples.