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NuSTAR and XMM-Newton Observations of the Neutron Star X-ray Binary 1RXS J180408.9-34205

Ludlam, R. M. and Miller, J. M. and Cackett, E. M. and Fabian, A. C. and Bachetti, M. and Parker, M. L. and Tomsick, J. A. and Barret, D. and Natalucci, L. and Rana, V. and Harrison, F. A. (2016) NuSTAR and XMM-Newton Observations of the Neutron Star X-ray Binary 1RXS J180408.9-34205. Astrophysical Journal, 824 (1). Art. No. 37. ISSN 0004-637X. doi:10.3847/0004-637X/824/1/37.

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We report on observations of the neutron star (NS) residing in the low-mass X-ray binary 1RXS J180408.9-34205 taken 2015 March by NuSTAR and XMM-Newton while the source was in the hard spectral state. We find multiple reflection features (Fe K_ɑ detected with NuSTAR; N vii, O vii, and O viii detected in the RGS) from different ionization zones. Through joint fits using the self-consistent relativistic reflection model relxill, we determine the inner radius to be ≤11.1 Rg . For a 1.4 M_☉ NS with a spin of a_* = 0, this is an inner disk radius of ⩽22.2 km. We find the inclination of the system to be between 18° and 29°. If the disk is truncated at a radius greater than the NS radius, it could be truncated by a boundary layer on the NS surface. It is also possible that the disk is truncated at the magnetospheric radius; conservative estimates would then imply B ⩽ (0.3-1.0) x 10^9 G at the magnetic poles, though coherent pulsations have not been detected and the source is not identified as a pulsar.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ludlam, R. M.0000-0002-8961-939X
Cackett, E. M.0000-0002-8294-9281
Fabian, A. C.0000-0002-9378-4072
Bachetti, M.0000-0002-4576-9337
Parker, M. L.0000-0002-8466-7317
Tomsick, J. A.0000-0001-5506-9855
Barret, D.0000-0002-0393-9190
Natalucci, L.0000-0002-6601-9543
Rana, V.0000-0003-1703-8796
Harrison, F. A.0000-0003-2992-8024
Additional Information:© 2016 The American Astronomical Society. Received 2015 November 20; accepted 2016 April 14; published 2016 June 8. We thank the referee for the generous and helpful comments. We also thank Javier Garcia for insightful discussion regarding the relxill model. E.M.C. gratefully acknowledges support from the National Science Foundation through CAREER award number AST-1351222. This research makes 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). This research also made use of data obtained with XMM-Newton, and the ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. L.N. wishes to acknowledge the Italian Space Agency (ASI) for financial support by ASI/INAF grant I/037/12/0-011/13.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)I/037/12/0-011/13
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Subject Keywords: accretion, accretion disks; relativistic processes; stars: neutron; X-rays: binaries
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2016-53
Issue or Number:1
Record Number:CaltechAUTHORS:20160707-103702416
Persistent URL:
Official Citation:R. M. Ludlam et al 2016 ApJ 824 37
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68888
Deposited By: Ruth Sustaita
Deposited On:07 Jul 2016 19:25
Last Modified:11 Nov 2021 04:06

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