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NuSTAR discovery of an unusually steady long-term spin-up of the Be binary 2RXP J130159.6-635806

Krivonos, Roman A. and Tsygankov, Sergey S. and Lutovinov, Alexander A. and Tomsick, John A. and Chakrabarty, Deepto and Bachetti, Matteo and Boggs, Steven E. and Chernyakova, Masha and Christensen, Finn E. and Craig, William W. and Fürst, Felix and Hailey, Charles J. and Harrison, Fiona A. and Lansbury, George B. and Rahoui, Farid and Stern, Daniel and Zhang, William W. (2015) NuSTAR discovery of an unusually steady long-term spin-up of the Be binary 2RXP J130159.6-635806. Astrophysical Journal, 809 (2). Art. No. 140. ISSN 0004-637X. doi:10.1088/0004-637X/809/2/140.

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We present spectral and timing analyses of Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the accreting X-ray pulsar 2RXP J130159.6–635806. The source was serendipitously observed during a campaign focused on the gamma-ray binary PSR B1259–63 and was later targeted for a dedicated observation. The spectrum has a typical shape for accreting X-ray pulsars, consisting of a simple power law with an exponential cutoff starting at ~7 keV with a folding energy of E_(fold) ≃ 18 keV. There is also an indication of the presence of a 6.4 keV iron line in the spectrum at the ~3σ significance level. NuSTAR measurements of the pulsation period reveal that the pulsar has undergone a strong and steady spin-up for the last 20 years. The pulsed fraction is estimated to be ~80%, and is constant with energy up to 40 keV. The power density spectrum shows a break toward higher frequencies relative to the current spin period. This, together with steady persistent luminosity, points to a long-term mass accretion rate high enough to bring the pulsar out of spin equilibrium.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Krivonos, Roman A.0000-0003-2737-5673
Tsygankov, Sergey S.0000-0002-9679-0793
Tomsick, John A.0000-0001-5506-9855
Chakrabarty, Deepto0000-0001-8804-8946
Bachetti, Matteo0000-0002-4576-9337
Boggs, Steven E.0000-0001-9567-4224
Christensen, Finn E.0000-0001-5679-1946
Fürst, Felix0000-0003-0388-0560
Harrison, Fiona A.0000-0003-2992-8024
Lansbury, George B.0000-0002-5328-9827
Rahoui, Farid0000-0001-7655-4120
Stern, Daniel0000-0003-2686-9241
Zhang, William W.0000-0002-1426-9698
Additional Information:© 2015 The American Astronomical Society. Received 2015 May 27; accepted 2015 July 16; published 2015 August 18. This research has made use of data obtained with NuSTAR, a project led by Caltech, funded by NASA and managed by NASA/JPL, and has utilized the NUSTARDAS software package, jointly developed by the ASDC (Italy) and Caltech (USA). This research has also made use of data obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States. A.L. and S.T. acknowledge support from Russian Science Foundation (grant 14-12-01287). Facilities: NuSTAR - The NuSTAR (Nuclear Spectroscopic Telescope Array) mission, XMM-Newton - Newton X-Ray Multimirror Mission satellite.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
European Space Agency (ESA)UNSPECIFIED
Russian Science Foundation14-12-01287
Subject Keywords:pulsars: individual (2RXP J130159.6–635806) – stars: emission-line, Be – X-rays: binaries
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2015-41
Issue or Number:2
Record Number:CaltechAUTHORS:20150801-084010223
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59133
Deposited By: Joy Painter
Deposited On:06 Aug 2015 17:50
Last Modified:10 Nov 2021 22:15

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