HI-observations of blue compact dwarf galaxies

We present HI-observations of 56 blue compact dwarf (BCD) galaxies of which 44 have been detected in the 21-cm line from neutral hydrogen with the 100-m radiotelescope at Effelsberg. Optical data (e.g., from NED) and HI data from other observers and telescopes are used to estimate the likelihood of confusion from other galaxies within the Effelsberg beam. The selected 29 BCD galaxies without any sign of confusion are used to infer several characteristic properties of the BCD galaxy population. In some respects, they resemble normal galaxies: e.g., the relations between global parameters like linear diameter A0 versus blue luminosity LB and the $M_{{\rm HI}}$/LB ratio vs. LB. At least five of these BCDGs emit milli-Jansky level radio continuum emission