A new X-ray outburst of XB 1745-25 in the globular cluster Terzan 5
ATel #101; Rudy Wijnands (MIT), Jeroen Homan (Brera Observatory), Ron Remillard (MIT)
on 2 Jul 2002; 22:12 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Rudy Wijnands (rudy@space.mit.edu)
Subjects: Radio, Infra-Red, Optical, X-ray, Request for Observations, Binary, Globular Cluster, Neutron Star, Transient
Referred to by ATel #: 15953
We report the detection of a new X-ray outburst of the neutron star
X-ray transient XB 1745-25 located in the globular cluster Terzan
5. The All Sky Monitor aboard the Rossi X-ray Timing Explorer began
detecting the source on or near 2002 June 25, when it rapidly rose to
87 +/- 7 mCrab at 2-12 keV. It then appears to have leveled off,
before rising again to 200 mCrab during June 29 to July 2. The source
was previously found to be in outburst in 2000 July - August
(Markwardt & Swank 2000, IAUC 7454 ), but has since been in
quiescence. The best known X-ray position can be obtained from an
archival Chandra/ACIS-I observation (performed on 2000 July 24) during
that outburst and is R.A.=17h48m05.244s, Dec.=-24 46' 47.7", with a
uncertainty of 0.5 arcseconds. This position includes a small shift to
tie the Chandra frame with the 2MASS J frame using a field star
detected in both data sets. Observations at all wavelengths are
strongly encouraged. A HST/NICMOS finding chart (F110W filter) can be
found in Edmonds et al. (2001, ApJ, 547, 829; their Figure 3 and the
source is located in the upper left corner in the ROSAT error circle).
