Swift/BAT detection of a new X-ray source, SWIFT J1656.3-3302, in the Galactic Center region
ATel #799; T. Okajima (JHU/NASA/GSFC), J. Tueller (NASA/GSFC), C. Markwardt (UMD/NASA/GSFC), M. Ajello (MPE Garching), V. Beckmann (UMBC/NASA/GSFC), T. Belloni (INAF/OAB), A. Falcone (PSU), O. Godet (U Leicester) , D. Grupe (PSU), S. Holland (USRA/NASA/GSFC), J. Kennea (PSU), K. Mukai (USRA/NASA/GSFC), R. Mushotzky (NASA/GSFC), R. Sambruna (NASA/GSFC)
on 27 Apr 2006; 20:41 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Jack Tueller (jack.tueller-1@nasa.gov)
Subjects: X-ray, Request for Observations, Transient
We report the detection of unidentified source SWIFT J1656.3-3302, which is located at RA = 254.08, Dec = -33.03 (J2000), galactic coordinates l = 350.60, b = 6.36. The source was detected at 5.7 sigma significance during the Swift/BAT hard X-ray survey (mid Dec. 2004 to mid Sept. 2005). The BAT spectrum (14-200 keV) is very hard with a photon index of 1.26 +/- 0.3. The flux is 1.0E-10 ergs/cm^2/sec. In the Galactic Center, the risk of source confusion is significant. Due to a small excess in the 14-25 keV band next to this source, we have expanded our error radius to 12 arcmin from the nominal value of 6. No counterpart has yet been identified, but Swift/XRT observations are planned. Based on our analysis of the INTEGRAL IBIS/ISGRI public data, the source is marginally detected at a much lower flux of ~6E-12 ergs/cm^2/sec. (Total on-source exposure is 2.6 Ms between 02/28/2003 and 10/20/2004.) Correcting to the same energy band, the source increased in brightness by more than a factor of 4 between the two observations.
