Pulse Frequency Fluctuations of Persistent Accretion Powered Pulsars

Abstract

In this study, we examine the long term torque noise fluctuations of persistent Xray binaries Her X-1, Vela X-1, GX 301-2, CEN X-3, 4U 1538-53, OAO 1657-415 and 4U 1626-67 using the historical pulse frequency measurements provided by CGRO/BATSE and Fermi/GBM. We find that known disk-fed sources exhibit $1/{\omega }^2$ red noise component in their power density spectra which is saturated over long timescales. On the other hand, wind-fed sources form a clear white noise component and the wind-fed sources with occasional transient disk formation imprint $1/\omega$ type flicker noise. We discuss their long-term timing noise properties based on the models to describe the power density spectrum of pulse frequency derivative fluctuations in terms of monochromatic and colored noise processes. Furthermore, we investigate the relation between measured timing noise strengths and other independently measured physical parameters. Despite the low number of sample sources, we suggest that noise strengths of these sources are correlated with their luminosities and uncorrelated with their magnetic fields strengths, implying that the dominant noise generating mechanism is accretion

23 pages, 8 figures. Accepted to be published in MNRAS

References in corpus (16)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars
• A Debris Disk Around An Isolated Young Neutron Star
• Assessing the Role of Spin Noise in the Precision Timing of Millisecond Pulsars
• Discovery of a flux-related change of the cyclotron line energy in Her X-1
• VLT/UVES spectroscopy of Wray 977, the hypergiant companion to the X-ray pulsar GX301-2
• Pulse phase resolved analysis of the HMXB Cen X-3 over two binary orbits
• The UTMOST pulsar timing programme II: Timing noise across the pulsar population
• A Mid-Infrared Counterpart to the Magnetar 1E 2259+586
• Magnetic fields of neutron stars in X-ray binaries
• A Clumpy Stellar Wind and Luminosity-Dependent Cyclotron Line Revealed by The First Suzaku Observation of the High-Mass X-ray Binary 4U 1538-522
• Discovery of a Glitch in the Accretion Powered Pulsar SXP 1062
• Neutron star dynamics under time dependent external torques
• Diagnostics of timing noise in middle aged pulsars
• Parameter estimation of a two-component neutron star model with spin wandering
• Rapid parameter estimation of a two-component neutron star model with spin wandering using a Kalman filter

Cited by in corpus (1)

• Timing analysis of Swift J0243.6+6124 with NICER and Fermi/GBM during the decay phase of the 2017-2018 outburst