Reverberation mapping of IC 4329A

Monitoring of the optical continuum with V-band photometry and broad emission-line flux variability with moderate-resolution spectroscopy allowed emission-line light curves to be measured for H{beta}, H{gamma}, and HeII{lambda}4686. We find a time delay of 16.3_-2.3_^+2.6^ days for H{beta}, a similar time delay of 16.0_-2.6_^+4.8^ days for H{gamma}, and an unresolved time delay of -0.6_-3.9_^+3.9^ days for HeII.

The time delay for H{beta} is consistent with the predicted value from the relationship between AGN luminosity and broad-line region radius, after correction for the ~2.4mag of intrinsic extinction at 5100{AA}. Combining the measured time delay for H{beta} with the broad emission-line width and an adopted value of <f>=4.8, we find a central supermassive black hole mass of M_BH_=6.8_-1.1_^+1.2^x10^7^M_{sun}_. Velocity-resolved time delays were measured across the broad H{beta} emission-line profile and may be consistent with an "M"-like shape.