  We report Giant Metrewave Radio Telescope (GMRT) 21cm observations of two
confirmed and one candidate low redshift damped Lyman-alpha systems (DLAS). HI
absorption was detected in the two confirmed systems, at z=0.2378 and z=0.5247,
with spin temperatures (Ts) of 2050 +- 200 K and 330 +- 70 K respectively. The
non-detection of absorption in the third (candidate) system places an upper
limit on its optical depth, which in turn implies a 3sigma lower limit of 850 K
on its spin temperature. Ground based K-band imaging observations (Turnshek et
al. 2000) have identified the low Ts absorber with a spiral galaxy while the
high Ts system appears to be an LSB galaxy. This continues the trend noted
earlier by Chengalur and Kanekar (2000) of low spin temperatures for DLAS
associated with spiral galaxies and high spin temperatures for those with no
such association.
  Combining these new results with 21cm observations from the published
literature, we find that (1)The 21 cm equivalent width (EW21) of DLAS increases
with increasing column density (NHI). Further, absorbers associated with spiral
galaxies have systematically higher EW21 at the same NHI than DLAS with no such
association, (2)DLAS at high redshift (z > 2) have small velocity spreads
(DeltaV), while, at low redshift (z < 2), both large and small DeltaV are
observed. These trends are in qualitative agreement with hierarchical models of
galaxy formation.
