2012A&A...539A..21D

Phase-targeted RXTE observations have allowed us to detect a transient 71.49±0.02s signal that is most likely to be originating from the supergiant fast X-ray transient IGR J17544-2619. The phase-folded light curve shows a possible double-peaked structure with a pulsed flux of ∼4.8x10^–12erg/cm2/s (3-10keV). Assuming the signal to indicate the spin period of the neutron star in the system, the provisional location of IGR J17544-2619 on the Corbet diagram places the system within the classical wind-fed supergiant XRB region. Such a result illustrates the growing trend of supergiant fast X-ray transients to span across both of the original classes of HMXB in P_orb-P_spin space.