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Polarization of accreting X-ray pulsars. I. A new model

Caiazzo, Ilaria and Heyl, Jeremy (2021) Polarization of accreting X-ray pulsars. I. A new model. Monthly Notices of the Royal Astronomical Society, 501 (1). pp. 109-128. ISSN 0035-8711. doi:10.1093/mnras/staa3428.

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A new window is opening in high-energy astronomy: X-ray polarimetry. With many missions currently under development and scheduled to launch as early as 2021, observations of the X-ray polarization of accreting X-ray pulsars will soon be available. As polarization is particularly sensitive to the geometry of the emission region, the upcoming polarimeters will shed new light on the emission mechanism of these objects, provided that we have sound theoretical models that agree with current spectroscopic and timing observation and that can make predictions of the polarization parameters of the emission. We here present a new model for the polarized emission of accreting X-ray pulsars in the accretion column scenario that for the first time takes into account the macroscopic structure and dynamics of the accretion region and the propagation of the radiation towards the observer, including relativistic beaming, gravitational lensing, and quantum electrodynamics. In this paper, we present all the details of the model, while in a companion paper, we apply our model to predict the polarization parameters of the bright X-ray pulsar Hercules X-1.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper ItemCode
Caiazzo, Ilaria0000-0002-4770-5388
Heyl, Jeremy0000-0001-9739-367X
Additional Information:© 2020 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2020 October 29. Received 2020 October 29; in original form 2020 May 27. Published: 05 November 2020. We would like to thank Michael Wolff, Peter Becker, and the XMAG collaboration for valuable input, and Sterl Phinney for useful comments. The research was supported by NSERC Canada, Compute Canada, a Burke Fellowship at Caltech, and a Four-Year Fellowship at UBC. Data Availability: All the figures in this work show calculations derived analytically from the equations presented throughout the paper. We apply our model to the accreting X-ray pulsar Hercules X-1 for different possible geometries in Paper II, and the values for the predicted polarization fraction and angle as function of phase and energy in those geometries are available in the public Github repository
Group:TAPIR, Walter Burke Institute for Theoretical Physics
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Walter Burke Institute for Theoretical Physics, CaltechUNSPECIFIED
University of British ColumbiaUNSPECIFIED
Subject Keywords:accretion, accretion discs – polarization – relativistic processes – scattering –X-rays: binaries – pulsars: general
Issue or Number:1
Record Number:CaltechAUTHORS:20210211-131223823
Persistent URL:
Official Citation:Ilaria Caiazzo, Jeremy Heyl, Polarization of accreting X-ray pulsars. I. A new model, Monthly Notices of the Royal Astronomical Society, Volume 501, Issue 1, February 2021, Pages 109–128,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108006
Deposited By: Tony Diaz
Deposited On:11 Feb 2021 21:37
Last Modified:16 Nov 2021 19:08

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