Pulse Profile Modeling (PPM), the technique used to infer mass, radius and geometric parameters for rotation-powered millisecond pulsars using data from the Neutron Star Interior Composition Explorer (NICER), relies on relativistic ray-tracing of thermal X-ray photons from hot spots on the neutron star surface to the observer. To verify our ray-tracing codes we have in the past conducted cross-tests for simple hot spot geometries, focusing primarily on the implementation of the space-time model. In this paper, we present verification for test problems that explore the more complex hot spot geometries that are now being employed in the NICER PPM analyses. We conclude that the accuracy of our computed waveforms is in general sufficiently high for analyses of current NICER data sets. We have however identified some extreme configurations where extra care may be needed.
@article{arxiv.2406.07285,
title = {Exploring Waveform Variations among Neutron Star Ray-tracing Codes for Complex Emission Geometries},
author = {Devarshi Choudhury and Anna L. Watts and Alexander J. Dittmann and M. Coleman Miller and Sharon M. Morsink and Tuomo Salmi and Serena Vinciguerra and Slavko Bogdanov and Sebastien Guillot and Michael T. Wolff and Zaven Arzoumanian},
journal= {arXiv preprint arXiv:2406.07285},
year = {2024}
}
Comments
Updated to version accepted by The Astrophysical Journal following their review process