H I distribution in an extremely faint dwarf irregular galaxy M81 dwA

We have used the Westerbork synthesis radio telescope to investigate the distribution of neutral hydrogen in an extremely faint, dwarf, irregular galaxy, M81 dwA, which was discovered by Lo and Sargent in a search for intergalactic H I clouds. M81 dwA has an absolute magnitude M/sub p/ roughly-equal-11.0 and an H I mass of 1.1 +- 0.1 x 107 M/sub sun/. The optical object has size 30'' x 60'', corresponding to 0.5 x 1.0 kpc2 at the distance to the M81 group. Its heliocentric radial velocity is v = 113 +- 2 km s-1, consistent with group membership. M81 dwA lies 29' from Holmberg II; the difference in redshift between the two objects makes it unlikely that M81 dwA is a dynamical satellite of Holmberg II