Arcsecond-Scale Radio Jets of Ultra-High-Energy Synchrotron Peak BL Lacs (UHBLs)

We present the arcsecond-scale jet structure and related radio properties for a sample of 9 UHBLs selected from Nieppola et al. (2006) with log(ν p e a k /H z)>20. Our preliminary results show that most of the UHBLs have compact structures, and their core dominance parameters are much larger than FR-I radio galaxies, suggesting that beaming may be prevalent in the jets of these sources.