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Published May 10, 2014 | Published
Journal Article Open

Timing and Flux Evolution of the Galactic Center Magnetar SGR J1745–2900

Abstract

We present the X-ray timing and spectral evolution of the Galactic Center magnetar SGR J1745−2900 for the first ~4 months post-discovery using data obtained with the Nuclear Spectroscopic Telescope Array and Swift observatories. Our timing analysis reveals a large increase in the magnetar spin-down rate by a factor of 2.60 ± 0.07 over our data span. We further show that the change in spin evolution was likely coincident with a bright X-ray burst observed in 2013 June by Swift, and if so, there was no accompanying discontinuity in the frequency. We find that the source 3–10 keV flux has declined monotonically by a factor of ~2 over an 80 day period post-outburst accompanied by a ~20% decrease in the source's blackbody temperature, although there is evidence for both flux and kT having leveled off. We argue that the torque variations are likely to be magnetospheric in nature and will dominate over any dynamical signatures of orbital motion around Sgr A*.

Additional Information

© 2014 The American Astronomical Society. Received 2013 November 20; accepted 2014 March 17; published 2014 April 21. This work was supported under NASA Contract No. NNG08FD60C, and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by theASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). We acknowledge the use of public data from the Swift data archive. This research has made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy. We thank the Swift SOT team for their work in scheduling. V.M.K. receives support from an NSERC Discovery Grant and Accelerator Supplement, from the Centre de Recherche en Astrophysique du Québec, an R. Howard Webster Foundation Fellowship from the Canadian Institute for Advanced Study, the Canada Research Chairs Program and the Lorne Trottier Chair in Astrophysics and Cosmology. R.F.A. receives support from a Walter C. Sumner Memorial Fellowship. A.M.B. was supported by NASA grants NNX-10-AI72G and NNX-13-AI34G. J.A.K. was supported by supported by NASA contract NAS5-00136. J.K.V.'s work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

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Created:
August 20, 2023
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October 26, 2023