Abstract In the study of perturbations around black hole configurations. whether an external source can influence the perturbation behavior is an interesting topic to investigate. When the source acts as an initial pulse. it is intuitively acceptable that the existing quasinormal frequencies will remain unchanged. https://www.roneverhart.com/2-Tier-Cardboard-Cupcake-Stand-with-White-Pink-Sweet-Shop-Design-Colorful-Candy-Themed-Dessert-Cart-Display-for-Pastr/