Reflecting on accretion in neutron star low-mass X-ray binaries

Abstract

Neutron star low-mass X-ray binaries accrete via Roche-lobe overflow from a stellar companion that is ≲ 1 M_⊙. The accretion disk in these systems can be externally illuminated by X-rays that are reprocessed by the accreting material into an emergent reflection spectrum comprised of emission lines superimposed onto the reprocessed continuum. Due to proximity to the compact object, strong gravity effects are imparted to the reflection spectrum that can be modeled to infer properties of the NS itself and other aspects of the accreting system. This short review discusses the field of reflection modeling in neutron star low-mass X-ray binary systems with the intention to highlight the work that was awarded the 2023 AAS Newton Lacy Pierce Prize, but also to consolidate key information as a reference for those entering this subfield.