  We present the X-ray broadband power spectral density function (PSD) of the
X-ray-luminous Seyfert IC 4329a, constructed from light curves obtained via
Rossi X-ray Timing Explorer monitoring and an XMM-Newton observation. Modeling
the 3-10 keV PSD using a broken power-law PSD shape, a break in power-law slope
is significantly detected at a temporal frequency of 2.5(+2.5,-1.7) * 10^-6 Hz,
which corresponds to a PSD break time scale T_b of 4.6(+10.1,-2.3) days. Using
the relation between T_b, black hole mass M_BH, and bolometric luminosity as
quantified by McHardy and coworkers, we infer a black hole mass estimate of
M_BH = 1.3(+1.0,-0.3) * 10^8 solar masses and an accretion rate relative to
Eddington of 0.21(+0.06,-0.10) for this source. Our estimate of M_BH is
consistent with other estimates, including that derived by the relation between
M_BH and stellar velocity dispersion. We also present PSDs for the 10-20 and
20-40 keV bands; they lack sufficient temporal frequency coverage to reveal a
significant break, but are consistent with the same PSD shape and break
frequency as in the 3-10 keV band.
