Cosmology Seminar Series - Image Differencing Algorithms for Stellar Explosions in the Universe

Difference Image Analysis (DIA) is a primary enabling technique in time-domain astronomy. The weather condition, photometric scaling, and sky background generally vary with time and across the field of view for astronomical imaging data acquired through optical or nearinfrared telescopes. These variations necessitate the homogenization of observed images using DIA to accurately measure the brightness of stellar explosions uncovered by the timedomain
surveys. In my talk, I will review the fundamental concepts of DIA and the prevalent methods employed in time-domain community, with a particular emphasis on our novel SFFT algorithm. The SFFT method can enable accurate image differencing in Fourier space with remarkable computational advancement. I will show some existing applications of SFFT method in time-domain surveys, such as the DECam program DESIRT in concert with the DESI operation for intermediate-redshift transients. Furthermore, I will highlight a transient
search framework we developed for JWST NIRCam/NIRISS observations and discuss our upcoming JWST Cycle 3 archival program for cosmic transients.