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Cyclotron resonant scattering feature simulations. II. Description of the CRSF simulation process

Schwarm, F.-W. and Ballhausen, R. and Falkner, S. and Schönherr, G. and Pottschmidt, K. and Wolff, M. T. and Becker, P. A. and Fürst, F. and Marcu-Cheatham, D. M. and Hemphill, P. B. and Sokolova-Lapa, E. and Dauser, T. and Klochkov, D. and Ferrigno, C. and Wilms, J. (2017) Cyclotron resonant scattering feature simulations. II. Description of the CRSF simulation process. Astronomy and Astrophysics, 601 . Art. No. A99. ISSN 0004-6361. doi:10.1051/0004-6361/201630250.

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Context. Cyclotron resonant scattering features (CRSFs) are formed by scattering of X-ray photons off quantized plasma electrons in the strong magnetic field (of the order 10^(12) G) close to the surface of an accreting X-ray pulsar. Due to the complex scattering cross-sections, the line profiles of CRSFs cannot be described by an analytic expression. Numerical methods, such as Monte Carlo (MC) simulations of the scattering processes, are required in order to predict precise line shapes for a given physical setup, which can be compared to observations to gain information about the underlying physics in these systems. Aims. A versatile simulation code is needed for the generation of synthetic cyclotron lines. Sophisticated geometries should be investigatable by making their simulation possible for the first time. Methods. The simulation utilizes the mean free path tables described in the first paper of this series for the fast interpolation of propagation lengths. The code is parallelized to make the very time-consuming simulations possible on convenient time scales. Furthermore, it can generate responses to monoenergetic photon injections, producing Green’s functions, which can be used later to generate spectra for arbitrary continua. Results. We develop a new simulation code to generate synthetic cyclotron lines for complex scenarios, allowing for unprecedented physical interpretation of the observed data. An associated XSPEC model implementation is used to fit synthetic line profiles to NuSTAR data of Cep X-4. The code has been developed with the main goal of overcoming previous geometrical constraints in MC simulations of CRSFs. By applying this code also to more simple, classic geometries used in previous works, we furthermore address issues of code verification and cross-comparison of various models. The XSPEC model and the Green’s function tables are available online (see link in footnote, page 1).

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Falkner, S.0000-0001-5209-991X
Pottschmidt, K.0000-0002-4656-6881
Wolff, M. T.0000-0002-4013-5650
Fürst, F.0000-0003-0388-0560
Marcu-Cheatham, D. M.0000-0001-8061-611X
Hemphill, P. B.0000-0002-1676-6954
Dauser, T.0000-0003-4583-9048
Wilms, J.0000-0003-2065-5410
Additional Information:© 2017 ESO. Article published by EDP Sciences. Received 14 December 2016; Accepted 23 January 2017; Published online 10 May 2017. This work has been partially funded by the Deutsche Forschungsgemeinschaft under DFG grant number WI 1860/11-1 and by the Deutsches Zentrum für Luft- und Raumfahrt under DLR grant numbers 50 OR 1113, 50 OR 1207, 50 OR 1410, and 50 OR 1411. We also acknowledge the Russian Foundation for Basic Research grant number 14-02-91345. M.T.W. is supported by the Chief of Naval Research and by the National Aeronautics and Space Administration Astrophysical Data Analysis Program. We thank the International Space Science Institute in Bern for inspiring team meetings. The fruitful discussions within the MAGNET collaboration also had a very positive impact on this work. The figures in this work have been produced using the slxfig package by Davis (2014).
Subject Keywords:X-rays: binaries – stars: neutron – methods: numerical
Record Number:CaltechAUTHORS:20170127-081638965
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Official Citation:Cyclotron resonant scattering feature simulations - II. Description of the CRSF simulation process. F.-W. Schwarm, R. Ballhausen, S. Falkner, G. Schönherr, K. Pottschmidt, M. T. Wolff, P. A. Becker, F. Fürst, D. M. Marcu-Cheatham, P. B. Hemphill, E. Sokolova-Lapa, T. Dauser, D. Klochkov, C. Ferrigno and J. Wilms. A&A, 601 (2017) A99. DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73769
Deposited By: Joy Painter
Deposited On:27 Jan 2017 19:09
Last Modified:11 Nov 2021 05:21

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