Signal, Model, Difference Imaging, and Transient Detection

 Effective detection of transient sources and accurate flux measurements are crucial in observational astronomy. Difference imaging algorithms, such as the Alard-Lupton (AL) algorithm, can produce difference images for transient detection and measurement. During my PhD research, I focused on testing and improving the Legacy Survey of Space and Time Difference Imaging Analysis (LSST DIA) pipeline using the synthetic source injection method. By adding simulated transient sources to astronomical images, we can trace the recovery of these synthetic sources from the difference images. Inspecting the morphology of detected sources from the difference images also provides insights into subtraction artifacts. In this talk, I will present the performance of the LSST DIA pipeline at different magnitudes of transient sources. Using flags from the detection table helps identify different types of subtraction artifacts. I will also explore the morphology and origin of these artifacts. Most non-saturation artifacts are caused by small perturbations, such as image registration errors. Furthermore, I will present possible improvements to the DIA algorithms.