Swift-XRT location of the ongoing Terzan 5 outburst
ATel #2920; M. Linares (MIT), D. Altamirano (UvA)
on 11 Oct 2010; 06:16 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Manuel Linares (firstname.lastname@example.org)
Subjects: X-ray, Binary, Globular Cluster, Neutron Star, Transient
Referred to by ATel #: 2922, 2924, 2929, 2932, 2933, 2935, 2939, 2940, 2946, 2952, 2958, 2974, 3000, 3044, 3264, 3892
IBIS-ISGRI observations on 2010-10-10 (Bordas et al. ATel #2919) as well as RXTE-PCA scans on 2010-10-09 (http://lheawww.gsfc.nasa.gov/users/craigm/galscan/html/EXO_1745-248.html) showed enhanced X-ray emission from the direction of the globular cluster Terzan 5. We analysed a ~500 s Swift-XRT observation of the field starting on 2010-10-10 01:32:05 UT, detecting one bright source at a position of RA=267.021 DEC=-24.781 (J2000; 3.6 arc-seconds error radius), consistent with Terzan 5 and about 5.3 arc-seconds from the Chandra location of the neutron star transient EXO 1745-248 (Heinke et al. 2003, ApJ, 590, 809).
Although Terzan 5 likely contains four additional quiescent neutron star low-mass X-ray binaries (Heinke et al. 2003) and the Swift-XRT cannot resolve them all, our result is consistent with the identification of EXO 1745-248 as the source currently in outburst (Bordas et al. ATel #2919).
We thank the Swift team for scheduling the observation.