The High Time Resolution Universe Survey - XI. Discovery of five recycled pulsars and the optical detectability of survey white dwarf companions

TL;DR

This paper reports the discovery of five recycled pulsars, including systems with heavy white dwarf companions, eclipsing behavior, and low-mass companions, expanding understanding of pulsar binary diversity.

Contribution

The study presents five newly discovered recycled pulsars with detailed orbital and companion characteristics, highlighting unique systems with heavy white dwarfs and eclipsing properties.

Findings

Discovery of five recycled pulsars with diverse binary properties

Identification of a potential heavy white dwarf companion in one system

Observation of eclipsing behavior in a redback pulsar

Abstract

We present the discovery of a further five recycled pulsar systems in the mid-Galactic latitude portion of the High Time Resolution Universe (HTRU) Survey. The pulsars have rotational periods ranging from 2 ms to 66 ms, and four are in binary systems with orbital periods between 10.8 hours and 9.0 days. Three of these binary systems are particularly interesting; PSR J1227-6208 has a pulse period of 34.5 ms and the highest mass function of all pulsars with near-circular orbits. The circular orbit suggests that the companion is not another neutron star, so future timing experiments may reveal one of the heaviest white dwarfs ever found ($>$ 1.3 M$_\odot$). Timing observations of PSR J1431$-$4715 indicate that it is eclipsed by its companion which has a mass indicating it belongs to the redback class of eclipsing millisecond pulsars. PSR J1653-2054 has a companion with a minimum mass of only $0.08$ M$_\odot$, placing it among the class of pulsars with low-mass companions. Unlike the majority of such systems, however, no evidence of eclipses is seen at 1.4 GHz.