HI observation of nearby galaxies - I. The first list of the Karachentsev catalog

We present HT observations of the galaxies in the first list of the Karachentsev catalog of previously unknown nearby dwarf galaxies (Karachentseva & Karachentsev 1998). This survey covers all known nearby galaxy groups within the Local Volume (i.e. within 10 Mpc) and their environment, that is about 25% of the total sky. A total of 257 galaxies have been observed with a detection rate of 60%. We searched a frequency band corresponding to heliocentric radial velocities from -470 km s(-1) to similar to+4000 km s(-1). Non-detections are either due to limited coverage in radial velocity, confusion with Local HI (mainly in the velocity range -140 km s(-1) to +20 km s(-1)), or lack of sensitivity for very weak emission. 25% of the detected galaxies are located within the Local Volume. Those galaxies are dwarf galaxies judged by their optical linear diameter (1.4 +/- 0.2 kpc on the average), their mean total HI mass (4.6 10(7) M-.), and their observed linewidths (39 km s(-1)).