Swift/BAT detection of the current outburst of XTE J1859+083
ATel #7037; H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC), W. Baumgartner (CRESST/GSFC/UMBC), J. Cummings (CRESST/GSFC/UMBC), N. Gehrels (GSFC), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. Palmer (LANL), T. Sakamoto (Aoyama Gakuin Univ.), M. Stamatikos (OSU/GSFC), T. Ukwatta (LANL)
on 9 Feb 2015; 22:07 UT
Credential Certification: Hans A. Krimm (Hans.Krimm@nasa.gov)
Subjects: X-ray, Binary, Neutron Star, Transient
The 9.8 s X-ray pulsar XTE J1859+083 was recently reported by the MAXI team to be in outburst (Negoro et al., ATel #7034). The BAT team confirms this outburst in the BAT hard X-ray transient monitor. The outburst was first detected in the 15-50 keV energy band on 26 Jan. 2015 and the count rate has been slowly rising since that time, reaching a level of 0.0075 +/- 0.002 ct s-1 cm-2 (~35 mCrab) on 9 February 2015 (MJD 57062).
The mean BAT position over 8 days of observations is
RA(J2000) = 18h 58m 57.60s (284.740 deg)
Dec(J2000) = +8d 15' 39.6'' (+8.261 deg),
with an estimated positional uncertainty of 2.5 arc minutes radius (90% confidence). This is consistent with the position reported by Corbet et al. (ApJ 695, 30, 2009) and strongly suggests that the source in outburst is indeed XTE J1859+083 and not a previously unknown transient. Swift/XRT observations have been approved, but will not be carried out until 13 Feb. 2015 due to a Sun-constraint.
Swift BAT hard X-ray transient monitor results for XTE J1859+083
