The very faint X-ray binary IGR J17062-6143: a truncated disc, no pulsations, and a possible outflow

van den Eijnden, J. et al. (2018) The very faint X-ray binary IGR J17062-6143: a truncated disc, no pulsations, and a possible outflow. Monthly Notices of the Royal Astronomical Society, 475(2), pp. 2027-2044. (doi:10.1093/mnras/stx3224)

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Abstract

We present a comprehensive X-ray study of the neutron star low-mass X-ray binary IGR J17062-6143, which has been accreting at low luminosities since its discovery in 2006. Analysing NuSTAR, XMM–Newton, and Swift observations, we investigate the very faint nature of this source through three approaches: modelling the relativistic reflection spectrum to constrain the accretion geometry, performing high-resolution X-ray spectroscopy to search for an outflow, and searching for the recently reported millisecond X-ray pulsations. We find a strongly truncated accretion disc at 77+22−18 gravitational radii (∼164 km) assuming a high inclination, although a low inclination and a disc extending to the neutron star cannot be excluded. The high-resolution spectroscopy reveals evidence for oxygen-rich circumbinary material, possibly resulting from a blueshifted, collisionally ionized outflow. Finally, we do not detect any pulsations. We discuss these results in the broader context of possible explanations for the persistent faint nature of weakly accreting neutron stars. The results are consistent with both an ultra-compact binary orbit and a magnetically truncated accretion flow, although both cannot be unambiguously inferred. We also discuss the nature of the donor star and conclude that it is likely a CO or O–Ne–Mg white dwarf, consistent with recent multiwavelength modelling.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Messenger, Dr Christopher
Authors: van den Eijnden, J., Degenaar, N., Pinto, C., Patruno, A., Wette, K., Messenger, C., Hernández Santisteban, J. V., Wijnands, R., Miller, J. M., Altamirano, D., Paerels, F., Chakrabarty, D., and Fabian, A. C.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Monthly Notices of the Royal Astronomical Society
Publisher:Oxford University Press
ISSN:0035-8711
ISSN (Online):1365-2966
Published Online:15 December 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Monthly Notices of the Royal Astronomical Society 475(2): 2027-2044
Publisher Policy:Reproduced in accordance with the publisher copyright policy
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