Brauer group and birational type of moduli spaces of torsionfree sheaves on a nodal curve

Let U^{'s}_{L}(n,d) be the moduli space of stable vector bundles of rank $n$ and fixed determinant L of degree d on a nodal curve Y. The moduli space of semistable vector bundles of rank n and degree $d$ will be denoted by U’Y(n,d). We calculate the Brauer groups of U^{'s}{L}(n,d)$. We study the question of rationality of $U_L^{{}^{\mathrm{\prime }}s}(n,d)$ and $U_Y^{\mathrm{\prime }}(n,d)$.