1 Introduction and Overview
Pulsars - rapidly rotating highly magnetised neutron stars - have resulted in many applications in
physics and astronomy. Striking examples include the confirmation of the existence of gravitational
radiation [314
] as predicted by general relativity [312, 313], the first detection of an extra-solar planetary
system [346, 244] and the discovery of the first double-pulsar binary system [44, 198]. The diverse zoo of
radio pulsars currently known is summarized in Figure 1.
Pulsar research has proceeded at a rapid pace since the first two versions of this article [179, 180].
Surveys mostly with the Parkes radio telescope [259], but also at Green Bank [232], Arecibo [228] and the
Giant Metre Wave Radio Telescope [231] have more than doubled the number of pulsars known back in
1997. The most exciting new results and discoveries from these searches are discussed in this updated
review.
We begin in Section 2 with an overview of the pulsar phenomenon, the key observed population
properties, the origin and evolution of pulsars and the main search strategies. In Section 3, we review
present understanding in pulsar demography, discussing selection effects and their correction techniques.
This leads to empirical estimates of the total number of normal and millisecond pulsars (see Section 3.3)
and relativistic binaries (see Section 3.4) in the Galaxy and has implications for the detection of
gravitational radiation from coalescing neutron star binaries which these systems are the progenitors of. Our
review of pulsar timing in Section 4 covers the basic techniques (see Section 4.2), timing stability
(see Section 4.3), binary pulsars (see Section 4.4), and using pulsars as sensitive detectors of
long-period gravitational waves (see Section 4.5). We conclude with a brief outlook to the future in
Section 5. Up-to-date tables of parameters of binary and millisecond pulsars are included in
Appendix A.
.
Pulsar research has proceeded at a rapid pace since the first two versions of this article [179
