Reverberation lags have recently been discovered in a handful of nearby , variable AGN .
Here , we analyze a \sim 100 ksec archival XMM-Newton observation of the highly variable AGN , ESO 113 - G010 in order to search for lags between hard , 1.5 – 4.5 keV , and soft , 0.3 – 0.9 keV , energy X-ray bands .
At the lowest frequencies available in the lightcurve ( \lesssim 1.5 \times 10 ^ { -4 } Hz ) , we find hard lags where the power-law dominated hard band lags the soft band ( where the reflection fraction is high ) .
However , at higher frequencies in the range ( 2 - 3 ) \times 10 ^ { -4 } Hz we find a soft lag of -325 \pm 89 s. The general evolution from hard to soft lags as the frequency increases is similar to other AGN where soft lags have been detected .
We interpret this soft lag as due to reverberation from the accretion disk , with the reflection component responding to variability from the X-ray corona .
For a black hole mass of 7 \times 10 ^ { 6 } M _ { \odot } this corresponds to a light-crossing time of \sim 9 R _ { g } / c , however , dilution effects mean that the intrinsic lag is likely longer than this .
Based on recent black hole mass-scaling for lag properties , the lag amplitude and frequency are more consistent with a black hole a few times more massive than the best estimates , though flux-dependent effects could easily add scatter this large .