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Spectral and Timing Properties of IGR J17091–3624 in the Rising Hard State During Its 2016 Outburst

Xu, Yanjun and García, Javier A. and Fürst, Felix and Harrison, Fiona A. and Walton, Dominic J. and Tomsick, John A. and Bachetti, Matteo and King, Ashley L. and Madsen, Kristin K. and Miller, Jon M. and Grinberg, Victoria (2017) Spectral and Timing Properties of IGR J17091–3624 in the Rising Hard State During Its 2016 Outburst. Astrophysical Journal, 851 (2). Art. No. 103. ISSN 1538-4357. doi:10.3847/1538-4357/aa9ab4.

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We present a spectral and timing study of the NuSTAR and Swift observations of the black hole candidate IGR J17091–3624 in the hard state during its outburst in 2016. Disk reflection is detected in each of the NuSTAR spectra taken in three epochs. Fitting with relativistic reflection models reveals that the accretion disk is truncated during all epochs with R_(in) > 10 r_g, with the data favoring a low disk inclination of ~30°–40°. The steepening of the continuum spectra between epochs is accompanied by a decrease in the high energy cutoff: the electron temperature kT_e drops from ~64 to ~26 keV, changing systematically with the source flux. We detect type-C QPOs in the power spectra with frequency varying between 0.131 and 0.327 Hz. In addition, a secondary peak is found in the power spectra centered at about 2.3 times the QPO frequency during all three epochs. The nature of this secondary frequency is uncertain; however, a non-harmonic origin is favored. We investigate the evolution of the timing and spectral properties during the rising phase of the outburst and discuss their physical implications.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Xu, Yanjun0000-0003-2443-3698
García, Javier A.0000-0003-3828-2448
Fürst, Felix0000-0003-0388-0560
Harrison, Fiona A.0000-0003-2992-8024
Walton, Dominic J.0000-0001-5819-3552
Tomsick, John A.0000-0001-5506-9855
Bachetti, Matteo0000-0002-4576-9337
Madsen, Kristin K.0000-0003-1252-4891
Grinberg, Victoria0000-0003-2538-0188
Additional Information:© 2017 The American Astronomical Society. Received 2017 August 10; revised 2017 November 2; accepted 2017 November 12; published 2017 December 18. We thank the anonymous referee for detailed and helpful comments. D.J.W. acknowledges support from an STFC Ernest Rutherford Fellowship. 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).
Group:NuSTAR, Space Radiation Laboratory, Astronomy Department
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)UNSPECIFIED
Subject Keywords:accretion, accretion disks – black hole physics – X-rays: binaries – X-rays: individual (IGR J17091–3624)
Issue or Number:2
Record Number:CaltechAUTHORS:20171219-092934959
Persistent URL:
Official Citation:Yanjun Xu et al 2017 ApJ 851 103
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83958
Deposited By: Tony Diaz
Deposited On:19 Dec 2017 19:22
Last Modified:15 Nov 2021 20:15

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