A Caltech Library Service

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

Kaspi, Victoria M. and Archibald, Robert F. and Bhalerao, Varun B. and Dufour, François and Gotthelf, Eric V. and An, Hongjun and Bachetti, Matteo and Beloborodov, Andrei M. and Boggs, Steven E. and Christensen, Finn E. and Craig, William W. and Grefenstette, Brian W. and Hailey, Charles J. and Harrison, Fiona A. and Kennea, Jamie A. and Kouveliotou, Chryssa and Madsen, Kristin K. and Mori, Kaya and Markwardt, Craig B. and Stern, Daniel and Vogel, Julia K. and Zhang, William W. (2014) Timing and Flux Evolution of the Galactic Center Magnetar SGR J1745–2900. Astrophysical Journal, 786 (2). Art. No. 84. ISSN 0004-637X. doi:10.1088/0004-637X/786/2/84.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


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*.

Item Type:Article
Related URLs:
URLURL TypeDescription
Kaspi, Victoria M.0000-0001-9345-0307
Archibald, Robert F.0000-0002-4017-8837
Bhalerao, Varun B.0000-0002-6112-7609
Gotthelf, Eric V.0000-0003-3847-3957
Bachetti, Matteo0000-0002-4576-9337
Boggs, Steven E.0000-0001-9567-4224
Christensen, Finn E.0000-0001-5679-1946
Grefenstette, Brian W.0000-0002-1984-2932
Harrison, Fiona A.0000-0003-2992-8024
Kennea, Jamie A.0000-0002-6745-4790
Kouveliotou, Chryssa0000-0003-1443-593X
Madsen, Kristin K.0000-0003-1252-4891
Mori, Kaya0000-0002-9709-5389
Markwardt, Craig B.0000-0001-9803-3879
Stern, Daniel0000-0003-2686-9241
Zhang, William W.0000-0002-1426-9698
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.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Centre de Recherche en Astrophysique du QuébecUNSPECIFIED
Canadian Institute for Advanced Research (CIFAR)UNSPECIFIED
Canada Research Chairs ProgramUNSPECIFIED
Lorne Trottier Chair in Astrophysics and CosmologyUNSPECIFIED
Walter C. Sumner Memorial FellowshipUNSPECIFIED
Department of Energy (DOE)DE-AC52-07NA27344
Issue or Number:2
Record Number:CaltechAUTHORS:20140618-104936732
Persistent URL:
Official Citation:Timing and Flux Evolution of the Galactic Center Magnetar SGR J1745–2900 Victoria M. Kaspi et al. 2014 ApJ 786 84
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46331
Deposited On:19 Jun 2014 19:08
Last Modified:10 Nov 2021 17:24

Repository Staff Only: item control page