  We report results from an investigation at hard X-rays (above 18 keV) and
soft X-rays (below 10 keV) of a sample of X-ray transients located on the
Galactic plane and detected with the bursticity method, as reported in the
latest 1,000 orbits INTEGRAL/IBIS catalog. Our main aim has been to individuate
those with X-rays characteristics strongly resembling Supergiant Fast X-ray
Transients (SFXTs). As a result, we found four unidentified fast X-ray
transients which now can be considered good SFXT candidates. In particular,
three transients (IGR J16374-5043, IGR J17375-3022 and IGR J12341-6143) were
very poorly studied in the literature before the current work, and our findings
largely improved the knowledge of their X-ray characteristics. The other
transient (XTE J1829-098) was previously studied in detail only below 10 keV,
conversely the current work provides the first detailed study in outburst above
18 keV. In addition we used archival infrared observations of the transients to
pinpoint, among the field objects, their best candidate counterpart. We found
that their photometric properties are compatible with an early type spectral
classification, further supporting our proposed nature of SFXTs. Infrared
spectroscopy is advised to confirm or disprove our interpretation. The reported
findings allowed a significant increase of the sample of candidate SFXTs known
to date, effectively doubling their number.
