16161

Supernova shocks have been long-favored as sites for accelerating cosmic rays (CR). They have been studied extensively in multiple wavebands to look for signatures of accelerated particles in the strong amplified magnetic fields created at shock fronts. In this proposal comma we present an optical-only study of CR acceleration comma by examining a specific class of astrophysical shocks known as .Balmer shocks.. Our target is supernova remnant (SNR) 0519-69.0 in the Large Magellanic Cloud (LMC) that has strong Balmer emission. We propose a third ACS-WFC observation of this SNR comma which will provide a virgul10 year baseline to measure the proper motion of the remnant. The well known distance to the LMC allows one to convert the proper motions to accurate shock velocities. The shock velocities comma combined with ground-based spectroscopic measurements of the broad H alpha line-widths will be used to calculate the CR acceleration efficiency over a broad range of shock velocities using state-of-the-art models. We demonstrate the significant reduction in shock velocity uncertainties resulting from increasing the time baseline from the current 1 year to 10 years. We highlight the importance of matching the observational configuration to minimize systematic errors in the proper motion. With the new observation comma we aim to reveal the dependence of CR acceleration efficiency on shock velocity.