quasi-period in 3C 273.

In Section 2, we present our observations and data reduction steps. In Section 3, we provide an overview of the two wavelet techniques used in our analysis: the continuous wavelet transform and the cross-wavelet transform. The results of these two techniques as well as significance tests are presented. We also discuss structure function analysis for the AGN in our sample. In Section 4 we argue that this 3.3 ks quasi-period in 3C 273 is consistent with what we would expect from oscillations in the accretion disk around the supermassive black hole based on current black hole mass estimates.

Observations and Data Reduction {#obssection}
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The 10 AGN in our sample were selected because they are bright and have [*XMM-Newton*]{} EPIC-PN camera observations which exceed 30 kiloseconds (ks). In total, we have 19 observations and each observation’s ID, date, length, and average counts are listed in Table \[obslog\]. All observations are in the energy range 0.75 to 10 keV and most were taken in small window mode, which has a readout time of 6 milliseconds (ms). The only exception is NGC 4151 Observation ID (Obs. ID): 0112830201, which was taken in full frame mode with a readout 