Space Telescope and Optical Reverberation Mapping Project 2: continuum reverberation mapping in Mrk 817

Mrk 817 is the subject of a year-long large intensive multi-wavelength monitoring campaign, involving Hubble, Swift, NICER, XMM, NuSTAR and ground-based observatories. X-ray and UV observations have revealed significant and highly variable absorption that was previously not seen. While the X-rays are faint, in contrast, the UV/optical continuum is at its brightest levels ever, ranging to over two times the historical mean values. Despite the presence of significant obscuring gas the UV/optical continuum remains highly variable, but that variability is uncorrelated with the observed X-ray flux. The variability within the UV and optical, however, is well correlated, and show reverberation lags with the longer wavelengths lagging the UV by several days. We will discuss these continuum reverberation mapping results and their implications for the structure of the inner region of the AGN in the context of this broader monitoring campaign.