We present further results from our onging optical spectrophotometric campaign at the Astronomical Observatory of Bologna in Loiano ( Italy ) on unidentified hard X–ray sources detected by INTEGRAL .
We observed spectroscopically the putative optical counterparts of the INTEGRAL sources IGR J00234+6141 , IGR J01583+6713 , IGR J06074+2205 , IGR J13091+1137 and IGR J20286+2544 .
We find that the first two are Galactic objects , namely a Cataclysmic Variable at a distance d \sim 300 pc and a Be/X transient High-Mass X–ray Binary ( HMXB ) located at \sim 6.4 kpc , respectively , whereas the last one is identified with MCG +04-48-002 , a Starburst/H ii galaxy at redshift z = 0.013 hiding a Seyfert 2 nucleus .
We identify IGR J13091+1137 as the ( likely Seyfert 2 type ) active nucleus of galaxy NGC 4992 , which we classify as an X–ray Bright , Optically Normal Galaxy ; this is the first example of this type of object to be detected by INTEGRAL , and one of the closest of this class .
We moreover confirm the possible Be/X nature of IGR J06074+2205 , and we estimate it to be at a distance of \sim 1 kpc .
We also reexamine the spectrum of the z = 0.087 elliptical radio galaxy PKS 0352 - 686 , the possible counterpart of the INTEGRAL source IGR J03532 - 6829 , and we find that it is a BL Lac .
Physical parameters for these sources are also evaluated by discussing our findings in the context of the available multiwavelength information .
These identifications further stress the importance of INTEGRAL in the study of the hard X–ray spectrum of Active Galactic Nuclei , HMXBs and Cataclysmic Variables .