| The various IBIS/ISGRI catalogs contain a large population of hard X-ray sources whose nature is still unknown. Even if >20 keV positional uncertainty provided by ISGRI is unprecedented, it is still to large to pinpoint the counterpart at other wavelengths, which is the only secure way to obtain a source identification. We, here, continue the work of trying to reveal the nature of these hard X-ray sources, starting with the analysis of X-ray data collected via focusing X-ray telescopes, in order to obtain arcsec accurate X-ray positions. We can then identify counterparts at infrared and optical wavelengths and try to unveil the nature of the sources. We analysed data from observations of 13 INTEGRAL sources made with the Swift satellite. The X-ray images obtained by the X-Ray Telescope instrument allowed us to find possible counterparts to the IGR sources with positional accuracy of a few arcsec. We then browsed the online catalogs (e.g., NED, SIMBAD, 2MASS, 2MASX, USNO B1.0) to search for counterparts at other wavelengths. We also made use of the X-ray spectral parameters in trying to identify the nature of those objects. For the 13 objects, we found possible counterparts at X-ray energies and identified the IR/optical and/or UV counterparts as seen with Swift/UVOT. In each case, we also discuss the likelihood of association of the X-ray and INTEGRAL source. We confirm the previously proposed classification of IGR J02524-0829 (Sey 2 AGN), J08023-6954 (RS CVn star), and J11457-1827 (Sey 1 AGN). For 7 of these sources we give the first identification of their nature: IGR J02086-1742, J12060+3818, J12070+2535, J13042-1020, and J13412+3022 are AGN, and J14488-5942 is a probable X-ray Binary, and for J03184-0014, although we question the association of the IGR and Swift sources, we classify the latter as an AGN. We suggest that IGR J15283-4443 is a Galactic source, and we cannot further classify the source. Finally, we question the association of IGR J11457-1827 and J23130+8608 with the X-ray sources we have found, and further question the genuineness of the former IGR source. |
