  We use a Wigner distribution-like function based on the strong field
approximation theory to obtain the time-energy distributions and the ionization
time distributions of electrons ionized by an XUV pulse alone and in the
presence of an infrared (IR) pulse. In the case of a single XUV pulse, although
the overall shape of the ionization time distribution resembles the
XUV-envelope, its detail shows dependence on the emission direction of the
electron and the carrier-envelope phase of the pulse, which mainly results from
the low-energy interference structure. It is further found that the electron
from the counter-rotating term plays an important role in the interference. In
the case of the two-color pulse, both the time-energy distributions and the
ionization time distributions change with varying IR field. Our analysis
demonstrates that the IR field not only modifies the final electron kinetic
energy but also changes the electron's emission time, which results from the
change of the electric field induced by the IR pulse. Moreover, the ionization
time distributions of the photoelectrons emitted from atoms with higher
ionization energy are also given, which show less impact of the IR field on the
electron dynamics.
