2024/06/24 by A. C. S. Readhead, Readhead, A. C. S.
Engineering · Physics and Astronomy · Social Sciences · #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #History and Developments in Astronomy #International Science and Diplomacy #Particle Accelerators and Free-Electron Lasers
paper · pdf · doi:10.48550/arxiv.2406.17164
openalex publication_date 2024/06/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Millisecond pulsars, like pulsars, have led to major advances in many areas of astronomy and physics. The discovery in 2023 of a cosmological gravitational wave (GW) stochastic background using millisecond pulsar timing arrays has focused attention on the importance of millisecond pulsars, to both multi-messenger astronomy and cosmology, and for identifying the origin of the GW stochastic background, which is hypothesized to be due to supermassive black hole binaries (SMBHBs). Unlike pulsars, however, for which the details of the discovery are well-known, those of millisecond pulsars are not well known. In particular, the details of the first crucial step in the discovery of millisecond pulsars, namely the discovery of interplanetary scintillation (IPS) in the radio source 4C 21.53, are known only to the author. This article presents a first-hand account of this crucial first step, which resulted ultimately in the discovery of millisecond pulses from this object. A brief description of interplanetary and interstellar scintillation and scattering is given in the Appendix.