Gamma-ray timing of redback PSR J2339–0533: Hints for gravitational quadrupole moment changes

We present the results of precision gamma-ray timing measurements of the binary millisecond pulsar PSR J2339–0533, an irradiating system of the “redback” type, using data from the Fermi Large Area Telescope. We describe an optimized analysis method to determine a long-term phase-coherent timing solu...

Full description

Saved in:
Bibliographic Details
Published inThe Astrophysical journal Vol. 807; no. 1
Main Authors Pletsch, Holger J., Clark, Colin J.
Format Journal Article
LanguageEnglish
Published United Kingdom 01.07.2015
Subjects
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
DATA ANALYSIS
GAMMA RADIATION
PROPER MOTION
PULSARS
QUADRUPOLE MOMENTS
QUADRUPOLES
STARS
TELESCOPES
Online AccessGet full text

Cover

More Information
Summary:We present the results of precision gamma-ray timing measurements of the binary millisecond pulsar PSR J2339–0533, an irradiating system of the “redback” type, using data from the Fermi Large Area Telescope. We describe an optimized analysis method to determine a long-term phase-coherent timing solution spanning more than six years, including a measured eccentricity of the binary orbit and constraints on the proper motion of the system. A major result of this timing analysis is the discovery of an extreme variation of the nominal 4.6 hr orbital period P{sub orb} over time, showing alternating epochs of decrease and increase. We inferred a cyclic modulation of P{sub orb} with an approximate cycle duration of 4.2 yr and a modulation amplitude of ΔP{sub orb}/P{sub orb}=2.3×10{sup −7}. Considering different possible physical causes, the observed orbital-period modulation most likely results from a variable gravitational quadrupole moment of the companion star due to cyclic magnetic activity in its convective zone.
ISSN:0004-637X
1538-4357