Swift/XRT Detection of the Hard X-ray Source SWIFT J1656.3-3302
ATel #835; 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), T. Okajima (JHU/NASA/GSFC), R. Sambruna (NASA/GSFC)
on 12 Jun 2006; 21:28 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Jack Tueller (jack.tueller-1@nasa.gov)
Subjects: X-ray, Gamma Ray, Request for Observations
Referred to by ATel #: 1270
Transient source SWIFT J1656.3-3302(ATel #799) has been detected with the Swift/XRT x-ray telescope. The BAT position was observed for a total of 4.3 ks starting on 2006-06-09 at 3:32:01 UT. The position of the source (SWIFT J165616.5-330209) is RA=16 56 16.56 dec=-33 02 09.3 J2000 with an error of 3.7". SWIFT J165616.5-330209 is well fit by an absorbed power law with index 1.38+/-0.3 and absorption (3.9+/-0.17)e21 cm^-2 consistent with an extragalactic source (galactic absorption=2.2e21 cm^-2). The absorbed flux in the XRT band (0.3-10 keV) is 5.6e-12 ergs cm^-2 s^-1 and the predicted flux in the BAT band (14-195 keV) is 4.0e-11 ergs cm^-2 s^-1, consistent with the BAT detection. No sources were detected by the UVOT in the XRT error circle at a limit of 20 mag in the U, UVW1, UVW2, UVW3 bands. The position of SWIFT J165616.5-330209 is consistent with the star USNO-A2.0 0525-24886745 (1"), the radio source NVSS J165616-330211 (3.6"), the IR source 2MASS 16561677-3302127 (4.4"), and the ROSAT source 1RXS J165616.6-330150 (19"). The ROSAT rate for 1RXS J165616.6-330150 was (2.3+/-1.1)e-2 cnts s^-1 and the estimated ROSAT rate for the XRT spectrum is 6.4e-2 cnts s^-1. If these two sources are the same, then some spectral variability is suggested. A second new weak x-ray source (SWIFT J165557.5-325944) was found at RA=16 55 57.50 dec=-32 59 44.3 J2000, but it is too soft (kT=1.5-0.6/+3.0) and too faint (flux=3e-13 ergs cm^-2 s^-1, 0.3-10 keV) to be the BAT source.
