High-resolution X-ray and radio maps of the millisecond pulsar

Abstract

The detection1 of a new pulsar in the radio source 4C21.53 with a period of 1.5 ms has raised important questions concerning the origin and evolution of galactic neutron stars. Before its discovery, we had been conducting radio and X-ray observations of 4C21.53 designed to place in context the intriguing properties of the source (extended emission, a low-frequency excess, and interstellar scintillation2). We present here the results of this programme including a stringent upper limit on any X-ray emission from the pulsar and high-resolution multi-frequency radio maps of the region which provide the best available pulsar position. We argue against any connection between the pulsar and the nearby extended radio emission region and comment on the constraints which the X-ray data place on the nature of this object.