Swift observations of Swift J1843.5-0343
ATel #3169; H. A. Krimm (CRESST/GSFC/USRA), J. A. Kennea (PSU), S. T. Holland (CRESST/GSFC/USRA)
on 16 Feb 2011; 15:04 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Hans A. Krimm (Hans.Krimm@nasa.gov)
Subjects: X-ray, Binary, Transient, Pulsar
The binary pulsar system Swift J1843.5-0343 (Krimm et al, ATel #3109; Strohmayer
& Markwardt, ATel #3121) was observed with Swift starting at 2011 Feb 15
00:27:25 UT for 1.9 ksec in PC mode and starting at 2011 Feb 15 03:46:37 for 2.0
ksec in WT mode. A point source was found in the Swift/XRT at at the astrometrically corrected (utilizing the method of Evans et al, 2009, MNRAS, 397, 1177) location:
RA (J2000): 18 43 34.75 (280.89481 deg)
Dec (J2000): -03 42 56.6 (-3.71571 deg)
90% Error radius: 2.7"
The faintness of the source (mean of 0.038 +/- 0.024 cts/s in 0.3-10 keV) makes
spectral fitting difficult. Freezing the photon index at 2, gives an absorption
of N_H = 2.2 (+1.0/-0.7) x 10^23 erg/s/cm-2 for the PC mode data.
No source was found within the XRT error circle in UVOT uvw1 images, which is consistent with the large
extinction in this direction.
We note that at the time of discovery (2011 Jan 9), Swift J1843.5-0343 was too
near the Sun for Swift XRT or UVOT observations. Observations were carried out
as soon as the source became visible. Since Feb 3, the source has been below
the detection threshold of Swift/BAT.
