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XMM-Newton and NuSTAR simultaneous X-ray observations of IGR J11215-5952

Sidoli, L. and Tiengo, A. and Paizis, A. and Sguera, V. and Lotti, S. and Natalucci, L. (2017) XMM-Newton and NuSTAR simultaneous X-ray observations of IGR J11215-5952. Astrophysical Journal, 838 (2). Art. No. 133. ISSN 1538-4357.

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We report the results of an XMM-Newton and NuSTAR coordinated observation of the Supergiant Fast X-ray Transient (SFXT) IGR J11215–5952, performed on 2016 February 14, during the expected peak of its brief outburst, which repeats every ~165 days. Timing and spectral analysis were performed simultaneously in the energy band 0.4–78 keV. A spin period of 187.0 (±0.4) s was measured, consistent with previous observations performed in 2007. The X-ray intensity shows a large variability (more than one order of magnitude) on timescales longer than the spin period, with several luminous X-ray flares that repeat every 2–2.5 ks, some of which simultaneously observed by both satellites. The broadband (0.4–78 keV) time-averaged spectrum was well deconvolved with a double-component model (a blackbody plus a power law with a high energy cutoff) together with a weak iron line in emission at 6.4 keV (equivalent width, EW, of 40 ± 10 eV). Alternatively, a partial covering model also resulted in an adequate description of the data. The source time-averaged X-ray luminosity was 10^(36) erg s^(−1) (0.1–100 keV; assuming 7 kpc). We discuss the results of these observations in the framework of the different models proposed to explain SFXTs, supporting a quasi-spherical settling accretion regime, although alternative possibilities (e.g., centrifugal barrier) cannot be ruled out.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Sidoli, L.0000-0001-9705-2883
Tiengo, A.0000-0002-6038-1090
Paizis, A.0000-0001-5067-0377
Lotti, S.0000-0002-3088-1561
Natalucci, L.0000-0002-6601-9543
Additional Information:© 2017 The American Astronomical Society. Received 2016 December 15; revised 2017 March 10; accepted 2017 March 13; published 2017 April 3. This work is based on data from observations with XMM-Newton, NuSTAR and Swift. XMM-Newton is an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). The NuSTAR mission is a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. This research made use of the NuSTAR DAS software package, jointly developed by the ASDC (Italy) and Caltech (USA). We thank N. Gehrels and the Swift team for making the Swift ToO possible. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester. We thank A. De Luca, S. Molendi (for helpful suggestions during EPIC data reduction), A. Bodaghee, F. Fürst, F. Gastaldello, K. Pottschmidt (for their useful advice on NuSTAR data), and K. Arnaud (for help with simftest in xspec). We are grateful to P. Esposito, S. Mereghetti and A.J. Bird for interesting and helpful discussions. We thank our anonymous referee for very constructive comments that helped to significantly improve the paper. We acknowledge financial contribution from the grant from PRIN-INAF 2014 "Toward a unified picture of accretion in High Mass X-Ray Binaries" (PI Sidoli) and from the agreement ASI-INAF NuSTAR I/037/12/0.
Subject Keywords:accretion, accretion disks – stars: neutron – X-rays: binaries – X-rays: individual (IGR J11215-5952)
Issue or Number:2
Record Number:CaltechAUTHORS:20170320-101004273
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Official Citation:L. Sidoli et al 2017 ApJ 838 133
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75235
Deposited By: Joy Painter
Deposited On:20 Mar 2017 17:16
Last Modified:03 Oct 2019 16:48

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