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NuSTAR and Swift observations of the black hole candidate XTE J1908+094 during its 2013 outburst

Tao, Lian and Tomsick, John A. and Walton, Dominic J. and Fürst, Felix and Kennea, Jamie and Miller, Jon M. and Boggs, Steven E. and Christensen, Finn E. and Craig, William W. and Gandhi, Poshak and Grefenstette, Brian W. and Hailey, Charles J. and Harrison, Fiona A. and Krimm, Hans A. and Pottschmidt, Katja and Stern, Daniel and Tendulkar, Shriharsh P. and Zhang, William W. (2015) NuSTAR and Swift observations of the black hole candidate XTE J1908+094 during its 2013 outburst. Astrophysical Journal, 811 (1). Art. No. 51. ISSN 0004-637X. doi:10.1088/0004-637X/811/1/51.

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The black hole candidate XTE J1908+094 went into outburst for the first time since 2003 in October 2013. We report on an observation with the Nuclear Spectroscopic Telescope Array (NuSTAR) and monitoring observations with Swift during the outburst. NuSTAR caught the source in the soft state: the spectra show a broad relativistic iron line, and the light curves reveal a ~40 ks flare with the count rate peaking about 40% above the non-flare level and with significant spectral variation. A model combining a multi-temperature thermal component, a power-law, and a reflection component with an iron line provides a good description of the NuSTAR spectrum. Although relativistic broadening of the iron line is observed, it is not possible to constrain the black hole spin with these data. The variability of the power-law component, which can also be modeled as a Comptonization component, is responsible for the flux and spectral change during the flare, suggesting that changes in the corona (or possibly continued jet activity) are the likely cause of the flare.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle Paper
Tomsick, John A.0000-0001-5506-9855
Walton, Dominic J.0000-0001-5819-3552
Fürst, Felix0000-0003-0388-0560
Kennea, Jamie0000-0002-6745-4790
Boggs, Steven E.0000-0001-9567-4224
Christensen, Finn E.0000-0001-5679-1946
Gandhi, Poshak0000-0003-3105-2615
Grefenstette, Brian W.0000-0002-1984-2932
Harrison, Fiona A.0000-0003-2992-8024
Krimm, Hans A.0000-0003-4348-6058
Pottschmidt, Katja0000-0002-4656-6881
Stern, Daniel0000-0003-2686-9241
Tendulkar, Shriharsh P.0000-0003-2548-2926
Zhang, William W.0000-0002-1426-9698
Additional Information:© 2015 The American Astronomical Society. Received 2015 June 5; accepted 2015 August 5; published 2015 September 18. 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 the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). Facilities: NuSTAR, Swift.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:accretion, accretion disks – black hole physics – stars: individual (XTE J1908+094) – X-rays: binaries
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2015-11
Issue or Number:1
Record Number:CaltechAUTHORS:20150802-092031817
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59139
Deposited By: Joy Painter
Deposited On:06 Aug 2015 18:23
Last Modified:10 Nov 2021 22:15

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