  We investigate the capability of LISA to measure the sky position of
equal-mass, nonspinning black hole binaries, combining for the first time the
entire inspiral-merger-ringdown signal, the effect of the LISA orbits, and the
complete three-channel LISA response. We consider an ensemble of systems near
the peak of LISA's sensitivity band, with total rest mass of 2\times10^6
M\odot, a redshift of z = 1, and randomly chosen orientations and sky
positions. We find median sky localization errors of approximately \sim3
arcminutes. This is comparable to the field of view of powerful electromagnetic
telescopes, such as the James Webb Space Telescope, that could be used to
search for electromagnetic signals associated with merging massive black holes.
We investigate the way in which parameter errors decrease with measurement
time, focusing specifically on the additional information provided during the
merger-ringdown segment of the signal. We find that this information improves
all parameter estimates directly, rather than through diminishing correlations
with any subset of well- determined parameters. Although we have employed the
baseline LISA design for this study, many of our conclusions regarding the
information provided by mergers will be applicable to alternative mission
designs as well.
