RXTE PCA and Swift BAT detects the Millisecond Pulsar Swift J1756.9-2508 in Outburst
C. B. Markwardt (U. Maryland and NASA/GSFC), , T. E. Strohmayer (NASA/GSFC), J. H. Swank (NASA/GSFC), S. E. Smith (WIS/NASA/GSFC),D. Pereira (Wyle IS and NASA/GSFC)
We report a detection of increased activity of the accreting millisecond X-ray pulsar Swift J1756.9-2508 observed with the RXTE-PCA monitoring on July 8, 9hr UTC. Increased flux is detected simultaneously on the Swift-BAT camera. RXTE-PCA follow up observations starting on July 13, 23hr UTC, detected the source in the 2-16 keV band at a flux level of approximately 19 mCrab, rising to 22 mCrab on July 14, 2hr UTC. Swift J1756.9-2508 was previously observed in outburst in June 2007 (Atel #1107), suggesting a recurrence time of approximately 2 years. Barycentered data at the Swift-XRT position (Krimm et al. 2007) show a peak in the power density spectrum which is entirely consistent with the 182.0658 Hz reported by Krimm et al. (2007). More PCA observations are planned. Follow-up observations at other wavelengths are encouraged.
x-ray,binary,neutron star,pulsar,star,transient,request for observations