X-ray Pulsations from the region of the Supergiant Fast X-ray Transient   IGR J17544-2619
  Phase-targeted RXTE observations have allowed us to detect a transient 71.49 \pm 0.02 s 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 ~4.8*10^-12 erg cm^-2 s^-1 (3-10 keV). 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 Porb - Pspin space. 
S. P. Drave, A. J. Bird, L. J. Townsend, A. B. Hill, V. A. McBride, V.   Sguera, A. Bazzano and D. J. Clark
astro-ph.HE