  Studying the Doppler shifts and the temperature dependence of Doppler shifts
in moss regions can help us understand the heating processes in the core of the
active regions. In this paper we have used an active region observation
recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) onboard Hinode
on 12-Dec-2007 to measure the Doppler shifts in the moss regions. We have
distinguished the moss regions from the rest of the active region by defining a
low density cut-off as derived by Tripathi et al. (2010). We have carried out a
very careful analysis of the EIS wavelength calibration based on the method
described in Young et al. (2012). For spectral lines having maximum sensitivity
between log T = 5.85 and log T = 6.25 K, we find that the velocity distribution
peaks at around 0 km/s with an estimated error of 4-5 km/s. The width of the
distribution decreases with temperature. The mean of the distribution shows a
blue shift which increases with increasing temperature and the distribution
also shows asymmetries towards blue-shift. Comparing these results with
observables predicted from different coronal heating models, we find that these
results are consistent with both steady and impulsive heating scenarios.
However, the fact that there are a significant number of pixels showing
velocity amplitudes that exceed the uncertainty of 5 km s$^{-1}$ is suggestive
of impulsive heating. Clearly, further observational constraints are needed to
distinguish between these two heating scenarios.
