  We present a systematic study of the steep decay emission from gamma-ray
bursts (GRBs) observed by the Swift X-Ray Telescope (XRT). In contrast to the
analysis described in recent literature, we produce composite Burst Alert
Telescope (BAT) and XRT light curves by extrapolating the XRT data (2-10 keV)
into the BAT energy range (15-25 keV) rather than extrapolating the BAT data
into the XRT energy band (0.3-10 keV). Based on the fits to the composite light
curves, we have confirmed the existence of an exponential decay component which
smoothly connects the BAT prompt data to the XRT steep decay for several GRBs.
We also find that the XRT steep decay for some of the bursts can be well fit by
a combination of a power-law with an exponential decay model. We discuss this
exponential component within the frame work of both the internal and the
external shock model.
