We present Giant Metrewave Radio Telescope ( GMRT ) HI 21cm emission images of the z = 0.009 damped Lyman- \alpha ( DLA ) absorber towards the QSO HS 1543+5921 .
The DLA has been earlier identified as a low surface brightness galaxy SBS 1543+593 ( [ Reimers & Hagen 1998 , Bowen et al .
2001a ] ) with small ( \sim 400 pc ) impact parameter to the QSO line of sight .
The extremely low redshift of the absorber allows us to make , for the first time , spatially resolved images of the 21cm emission ; besides the HI mass , this also enables us to determine the velocity field of the galaxy and , hence , to estimate its dynamical mass .
We obtain a total HI mass of \sim 1.4 \times 10 ^ { 9 } M _ { \odot } , considerably smaller than the value of M _ { HI } ^ { * } determined from blind 21cm emission surveys .
This continues the trend of low HI mass in all low redshift DLAs for which HI emission observations have been attempted .
We also find that the QSO lies behind a region of low local HI column density in the foreground galaxy .
This is interesting in view of suggestions that DLA samples are biased against high HI column density systems .
Finally , the dynamical mass of the galaxy is found to be M _ { dyn } \sim 5 \times 10 ^ { 9 } M _ { \odot } .