  Through an optical campaign performed at 4 telescopes located in the northern
and the southern hemispheres, we have obtained optical spectroscopy for 75
counterparts of unclassified or poorly studied hard X-ray emitting objects
detected with Swift/BAT and listed in the 54 month Palermo BAT catalogue. All
these objects have also observations taken with Swift/XRT, ROSAT or Chandra
satellites which allowed us to reduce the high energy error box and pinpoint
the most likely optical counterpart/s. We find that 69 sources in our sample
are Active Galactic Nuclei (AGNs); of them, 35 are classified as type 1 (with
broad and narrow emission lines), 33 are classified as type 2 (with only narrow
emission lines) and one is an high redshift QSO; the remaining 6 objects are
galactic cataclysmic variables (CVs). Among type 1 AGNs, 32 are objects of
intermediate Seyfert type (1.2-1.9) and one is Narrow Line Seyfert 1 galaxy;
for 29 out of 35 type 1 AGNs, we have been able to estimate the central black
hole mass and the Eddington ratio. Among type 2 AGNs, two display optical
features typical of the LINER class, 3 are classified as transition objects, 1
is a starburst galaxy and 2 are instead X-ray bright, optically normal
galaxies. All galaxies classified in this work are relatively nearby objects
(0.006 - 0.213) except for one at redshift 1.137.

High Energy Astrophysical Phenomena