# TESS Program G05118 Title: Testing X-Ray Reprocessing In Mrk 359 With TESS, Nicer, And Swift PI: Fausnaugh, Michael - Massachusetts Institute Of Technology Type: SMALL Summary: It is often assumed that X-ray variations in AGN drive UV/optical variations by heating the outer parts of the accretion disk. However, AGN X-ray and UV/optical light curves are often poorly correlated, which challenges this assumption. We can test whether or not AGN UV/optical variations are reprocessed X-rays by searching for a correlation between X-ray reflection features measured by NICER and optical variations measured by TESS; such a correlation must exist if X-ray reprocessing drives AGN variability. Simultaneous TESS and Swift data can also constrain the total reprocessed energy and predict the X-ray reflection strength, which provides a second test. We propose coordinated observations of Mrk 359 with TESS, NICER, and Swift to carry out these tests of X-ray reprocessing. # Sector 057 targets observed (2 min: 1, 20 s: 0) 10001665379,21.8856,19.1788,13.36,G05118