Name of the Speaker(s):Tapio Pursimo, Aimo Sillanpaa, Leo Takalo, Kari Nilsson and Jochen Heidt
Institution: Tuorla Observatory
Title of the communication: HIGH RESOLUTION IMAGING OF BL LAC OBJECTS AT NOT
Preliminary abstract (12 lines max.):
We present first results of a high resolution imaging study of radio selected BL Lac-objects from the 1 Jy sample. Our sample contains 30 objects ($\delta$$>$-20$^\circ$) observable at the Nordic Optical Telescope (NOT).

The main goals of this project are:
- Detection of previously unknown host galaxies.
- Study of their morphology (are all BL Lac hosts ellipticals?)
- Probing the AGN activity - interaction scenario
- Searching for BL Lac objects,which are affected by gravitational microlensing
- Study of the cluster environment and comparison with those of FR I and II radio galaxies

During the first observing run in October 1995, we could obtain deep images of 13 objects, under good or excellent seeing conditions (FWHM 0$^{\prime \prime}$.5-0$^{\prime \prime}$.9). We will show several examples of BL Lac objects with close companions and their host galaxiesand present a previously unknown microlensing candidate.