Pulse profiles of accreting neutron stars - A review of analysis methods, observations, and theoretical models

Katja Pottschmidt; Peter Kretschmar; Ekaterina Sokolova-Lapa; Elena Ambrosi; Ralf Ballhausen; Peter A. Becker; Katrin Berger; McKinley C. Brumback; Joel B. Coley; Robin H. D. Corbet; Antonino D'Aì; Megan E. DeCesar; Carlo Ferrigno; Felix Fürst; Nazma Islam; Ingo Kreykenbohm; Vicente Madurga-Favieres; Pragati Pradhan; Jakob Stierhof; Philipp Thalhammer; Brent F. West; Michael T. Wolff; Aafia Zainab; Nicolas Zalot; Christian Malacaria; Richard E. Rothschild; Jörn Wilms; Kent S. Wood

arXiv · 2608.20876

Pulse profiles of accreting neutron stars - A review of analysis methods, observations, and theoretical models

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Abstract

X-ray pulsars are highly magnetized ($B\sim 10^{12}$ G) neutron stars accreting from a donor star. Their characteristic X-ray emission arises from accreted material decelerated from relativistic velocities near the magnetic poles of the neutron star. As our line of sight onto the magnetic poles changes with the rotation of the neutron star, the X-rays are periodically modulated, resulting in X-ray pulsations. The shape of the pulse profiles depends on the physics of the interaction between the bright X-rays from the magnetic poles with the infalling matter, the location of the magnetic poles on the neutron star with respect to its spin axis, and on the properties of the space-time around the neutron star. In this review we give a pedagogical introduction to the accretion mechanisms operating in the various types of accreting neutron star systems and the observational techniques used to characterize the pulse profiles. We summarize how the pulse profiles depend on X-ray luminosity and energy and discuss the attempts to connect theoretically these observables with the physical accretion mechanisms. We conclude with an outline of future observational needs and further developments for theoretical models of magnetic accretion.

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Katja Pottschmidt, Peter Kretschmar, Ekaterina Sokolova-Lapa, Elena Ambrosi, Ralf Ballhausen, Peter A. Becker, Katrin Berger, McKinley C. Brumback, Joel B. Coley, Robin H. D. Corbet, Antonino D'Aì, Megan E. DeCesar, Carlo Ferrigno, Felix Fürst, Nazma Islam, Ingo Kreykenbohm, Vicente Madurga-Favieres, Pragati Pradhan, Jakob Stierhof, Philipp Thalhammer, Brent F. West, Michael T. Wolff, Aafia Zainab, Nicolas Zalot, Christian Malacaria, Richard E. Rothschild, Jörn Wilms, Kent S. Wood. 2026-08-21. Pulse profiles of accreting neutron stars - A review of analysis methods, observations, and theoretical models. https://arxiv.org/abs/2608.20876

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