The Pulsar in the Crab Nebula

TL;DR

This paper reviews the diverse observational phenomena of the Crab pulsar across radio and gamma wavelengths, highlighting the complexity of its emission mechanisms and the challenges in developing a unified theoretical understanding.

Contribution

It provides an overview of previous studies on the Crab pulsar's emission properties, emphasizing potential connections between radio and gamma-ray emissions and discussing possible common mechanisms.

Findings

Diverse emission phenomena observed across wavelengths

Irregularities in pulsar slowdown and pulse emission

Potential links between radio and gamma-ray emission mechanisms

Abstract

The Crab pulsar belongs to one of the most studied stellar objects in the sky. Since its accidental detection in 1968, its pulsed emission has been observed throughout most of the electromagnetic spectrum. Although currently one of more than 2000 known pulsars, its way of work has remained not understood making the Crab pulsar an object of continuous studies and interest. Referring to the pulsed emission of the Crab pulsar only at radio wavelengths, it reveals a diversity of different phenomena. They range from deviations of the predicted slowing down process of the pulsar with time (long time phenomena) to an irregularity of its single pulse emission (short time phenomena). Similar and different kinds of deviations are observed at other wavelengths. Consequently, the Crab pulsar provides a large diversity of different emission characteristics which have remained difficult to interpret with a uniform theoretical approach including all observed properties. Since a review of all currently examined properties of the Crab pulsar is beyond the scope of this paper, its goal is to give an overview of previous studies of the Crab pulsar predominantly at radio and gamma-wavelengths with an emphasis on a possible connection to its radio single pulse emission. A discussion of a possible identification of common emission mechanisms is given.