The clumpy absorber in the high-mass X-ray binary Vela X-1

Journal article

Publication Details

Author(s): Grinberg V, Hell N, El Mellah I, Neilsen J, Sander AAC, Leutenegger M, Furst F, Huenemoerder DP, Kretschmar P, Kühnel M, Martinez-Nunez S, Niu S, Pottschmidt K, Schulz NS, Wilms J, Nowak MA
Journal: Astronomy & Astrophysics
Publication year: 2017
Volume: 608
ISSN: 1432-0746


Bright and eclipsing, the high-mass X-ray binary Vela X-1 offers a unique opportunity to study accretion onto a neutron star from clumpy winds of O/B stars and to disentangle the complex accretion geometry of these systems. In Chandra-HETGS spectroscopy at orbital phase similar to 0.25, when our line of sight towards the source does not pass through the large-scale accretion structure such as the accretion wake, we observe changes in overall spectral shape on timescales of a few kiloseconds. This spectral variability is, at least in part, caused by changes in overall absorption and we show that such strongly variable absorption cannot be caused by unperturbed clumpy winds of O/B stars. We detect line features from high and low ionization species of silicon, magnesium, and neon whose strengths and presence depend on the overall level of absorption. These features imply a co-existence of cool and hot gas phases in the system, which we interpret as a highly variable, structured accretion flow close to the compact object such as has been recently seen in simulations of wind accretion in high-mass X-ray binaries.

FAU Authors / FAU Editors

Wilms, Jörn Prof. Dr.
Professur für Astronomie und Astrophysik

External institutions with authors

European Space Agency (ESA)
Katholieke Universiteit Leuven (KUL) / Catholic University of Leuven
Lawrence Livermore National Laboratory
Massachusetts Institute of Technology (MIT)
Universidad de Cantabria (UC)
Universität Potsdam
University of Maryland, Baltimore County
Villanova University

How to cite

Grinberg, V., Hell, N., El Mellah, I., Neilsen, J., Sander, A.A.C., Leutenegger, M.,... Nowak, M.A. (2017). The clumpy absorber in the high-mass X-ray binary Vela X-1. Astronomy & Astrophysics, 608.

Grinberg, Victoria, et al. "The clumpy absorber in the high-mass X-ray binary Vela X-1." Astronomy & Astrophysics 608 (2017).


Last updated on 2019-04-06 at 14:08

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