Binary and Millisecond Pulsars

TL;DR

This comprehensive review surveys binary and millisecond radio pulsars, detailing their phenomenology, demography, and timing-based applications. It synthesizes progression from the lighthouse emission model through population corrections and beaming, to relativistic tests of gravity and gravitational-wave detection via pulsar timing arrays. The work highlights the explosion in known systems due to major surveys, the role of timing in constraining neutron-star masses and the equation of state, and the potential for upcoming facilities (e.g., SKA) to dramatically enhance low-frequency gravitational-wave astronomy. It underscores that only a small fraction of the Galactic pulsar population is currently observed, and that future discoveries will deepen our understanding of compact-object evolution, gravitational physics, and cosmological gravitational waves.

Abstract

We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5 solar masses, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e=0.44) orbit around an unevolved companion.

Figures (31)

• Figure 1: Venn diagram showing the numbers and locations of the various types of radio pulsars known as of September 2008. The large and small Magellanic clouds are denoted by LMC and SMC.
• Figure 2: The rotating neutron star (or "lighthouse") model for pulsar emission. Animation designed by Michael Kramer.
• Figure 3: The $P \hbox{--} \dot{P}$ diagram showing the current sample of radio pulsars. Binary pulsars are highlighted by open circles. Lines of constant magnetic field (dashed), characteristic age (dash-dotted) and spin-down energy loss rate (dotted) are also shown.
• Figure 4: A variety of integrated pulse profiles taken from the available literature. References: Panels a, b, d, f gl98, Panel c bjb97, Panels e, g, i kxl98, Panel h bbm97. Each profile represents 360 degrees of rotational phase. These profiles are freely available from an online database epndb.
• Figure 5: A recent phenomenological model for pulse shape morphology. The neutron star is depicted by the grey sphere and only a single magnetic pole is shown for clarity. Left: a young pulsar with emission from a patchy conal ring at high altitudes from the surface of the neutron star. Right: an older pulsar in which emission emanates from a series of patchy rings over a range of altitudes. Centre: schematic representation of the change in emission height with pulsar age. Figure designed by Aris Karastergiou and Simon Johnston kj07.