Fat cosmic ray tracks in charge-coupled devices

Cosmic rays are particles from the upper atmosphere, which often leave bright spots and trails in images telescope charge-coupled devices (CCDs). We investigate so-called “fat” cosmic seen Vera C. Rubin Observatory Subaru Telescope. These tracks much wider brighter than typical ray therefore more capable of obscuring data science images. By understanding origins these tracks, we can better ensure that they do not interfere with on-sky data. compare properties to simulated theoretical models identify both causing as well reason for their excess spread. propose origin is protons, deposit greater charge CCDs due lower velocities. The generated charges then repel each other while drifting through detector, resulting a track tracks.