Swift XRT Observation of 1E 1841-045
ATel #5420; Robert Archibald, Paul Scholz, Victoria Kaspi (McGill University)
on 26 Sep 2013; 02:59 UT
Credential Certification: Victoria Kaspi (vkaspi@physics.mcgill.ca)
Subjects: X-ray, Neutron Star, Soft Gamma-ray Repeater, Pulsar
We report on Swift XRT observations made following an X-ray/soft gamma-ray burst detected by Fermi-GBM on 13 September 2013 (GCNs 15245, 15228) from the direction of magnetar 1E 1841-045 in the supernova remnant Kes 73. As part of an ongoing monitoring campaign of 1E 1841-045, as well as several other magnetars with the Swift XRT, we observed the source on 16 September 2013 for 4.4 ks. We detect no significant change in the X-ray flux relative to pre-burst epochs: we measure an absorbed 2-10 keV flux of 2.48^(+0.07)_(-0.09) E-11 ergs/s/cm^2 for the 16 September 2013 observation, compared with an average of 2.484^(+0.006)_(-0.06) E-11 ergs/s/cm^2 for observations for the 2 years prior, or 2.39^(+0.10)_(-0.17) E-11 ergs/s/cm^2 for the prior observation on 24 August, 2013. The observation was also searched for short X-ray bursts; none was detected. Based on a phase-coherent timing analysis including data from approximately one year prior to the burst, we rule out any sudden change in the frequency of this 11.8-s pulsar at the burst epoch of larger than 2x10^{-7} Hz (3 sigma). Thus, there is no evidence from the Swift XRT observation following the 13 September burst for any additional radiative or timing anomalies from this source.
