The role of external trigger for SF in blue compact galaxies: implications from statistics of companion galaxies

The relative role of various trigger mechanisms for onset of SF bursts inactively star-forming galaxies is still poorly understood. Following the study by Taylor et al. (1995) we extended the search for possible companions of various mass for BCG/HII galaxies to a much larger statistical sample of86 BCGs with EW([OIII] λ5007 Å > 45 and V < 6000km s^sup -1^. With the data on the radial velocities of galaxies in the BCGs environment we found that 33(38%) of the studied BCGs are companions of significantly brighter galaxies (for most of them projection distance < 300 kpc).24 galaxies (28%) have similar or low-mass companions and other 13 BCGs (15%) are either certain, or probable mergers. Only 16 BCGs (18.5%) have no detected companions. For some of them potential candidate companions do exist with still unknown velocities. Summarizing, we conclude that in 80% (or more) of BCGs from the statistical subsample in the zone of the Second Byurakan survey star formation bursts are triggered by various interactions with other galaxies.[PUBLICATION ABSTRACT]