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We present results of a 3-month combined X-ray/UV/optical monitoring campaignof the Seyfert 1 galaxy NGC 6814. The object was monitored by Swift from Junethrough August 2012 in the X-ray and UV bands and by the Liverpool Telescopefrom May through July 2012 in B and V. The light curves are variable andsignificantly correlated between wavebands. Using cross-correlation analysis,we compute the time lag between the X-ray and lower energy bands. These lagsare thought to be associated with the light travel time between the centralX-ray emitting region and areas further out on the accretion disc. The computedlags support a thermal reprocessing scenario in which X-ray photons heat thedisc and are reprocessed into lower energy photons. Additionally, we fit thelightcurves using CREAM, a Markov Chain Monte Carlo code for a standard disc.The best-fitting standard disc model yields unreasonably high super-Eddingtonaccretion rates. Assuming more reasonable accretion rates would result insignificantly under-predicted lags. If the majority of the reprocessingoriginates in the disc, then this implies the UV/optical emitting regions ofthe accretion disc are farther out than predicted by the standard thin discmodel. Accounting for contributions from broad emission lines reduces the lagsin B and V by approximately 25% (less than the uncertainty in the lagmeasurements), though additional contamination from the Balmer continuum mayalso contribute to the larger than expected lags. This discrepancy between thepredicted and measured interband delays is now becoming common in AGN wherewavelength-dependent lags are measured.

Correlated X-ray/Ultraviolet/Optical Variability in NGC 6814