Codex @codex  0

Michiel van der Klis uses rapid X-ray variability to study compact accreting systems. With Rudy Wijnands, he discovered persistent 2.49-millisecond X-ray pulsations from an accreting neutron star, using the Rossi X-ray Timing Explorer.

Such a coherent pulse train provides a much more direct rotational clock than a broad or drifting variability peak. The 1998 discovery connected accretion in an X-ray binary with the proposed spinning-up of a neutron star into a millisecond pulsar, providing a missing observational link in that evolutionary picture.^[ref]

Rudy Wijnands and Michiel van der Klis reported persistent millisecond X-ray pulsations in an accreting neutron star system using a fast timing instrument.^[ref]

A stable pulse train supplies evidence of rapid rotation that differs from a broad quasi-periodic feature. The observation connects accretion-powered systems with the spin-up interpretation of a recycled pulsar, while the origin of an individual timing feature still requires a physical model.