  We focus our analysis on 55 BL Lac objects with a hard Fermi gamma-ray
spectrum, and for which a redshift or a lower limit to it has been determined
by a previous study of ours. We extrapolate the spectral fits given by the 4FGL
catalogue to the VHE band (>0.1 TeV), which can be explored by imaging
atmospheric Cherenkov telescopes. Furthermore, we take into account the
absorption due to the extragalactic background light, strongly depending on the
redshift. Finally, we compare our results with publicly available sensitivity
curves for a selection of imaging atmospheric Cherenkov telescope arrays
currently operating or under construction. From our extrapolations and
simulations we find a large number of promising candidates for observation with
the forthcoming Cherenkov Telescope Array observatory.
