Lei Hu (胡镭) from PMO will give a talk at 11:30AM Nov. 12th (Thursday) with a title of "Image Subtraction Algorithms for Massive Transient Surveys" and the abstract:

Variable source identification from astronomical observations has played an indispensable role in time-domain astrophysics. Since the point spread function (PSF) of images from ground-based optical telescopes generally varies across the image field due to atmospheric seeing and instrumental optical distortion, image subtraction is essential to match the PSF and sensitivity variations for detecting transients. An efficient algorithm on the calculation of image differences, that can be fully parallelized, is highly desirable for future massive surveys such as WFST and LSST. In this talk, I will give a brief introduction to the popular convolution-based methods, which have been applied in Dark Energy Survey (DES) and Zwicky Transient Facility (ZTF). In addition, I will also talk about a novel image subtraction algorithm we developed in Fourier Space, called SFFT. It has been tested extensively in real astronomical data taken by a variety of telescopes, including DECam, TMTS, AST3-II and TESS. Unlike other methods, SFFT can make use of all statistically valid pixels in the image for the construction of the image matching.