... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... The rates of type Ia supernovae from double degenerate mergers channel in different star formation models (left panel), and the rate contribution function to the present-day ( t disc = 10Gyr) supernovae rates in the thin disc (right panel). ... We have compared the impact of different star-formation models on the rates and numbers of DDs and on the rates of type Ia (SNIa) and core-collapse supernovae (ccSN). ...