Accretion torques and motion of the hot spot on the accreting millisecond pulsar XTE J1807-294

Abstract

We present a coherent timing analysis of the 2003 outburst of the accreting millisecond pulsar XTE J1807-294. We find an upper limit for the spin frequency derivative of 5E-14 Hz/s. The sinusoidal fractional amplitudes of the pulsations are the highest observed among the accreting millisecond pulsars and can reach values of up to 27% (2.5-30 keV). The pulse arrival time residuals of the fundamental follow a linear anti-correlation with the fractional amplitudes that suggests hot spot motion over the surface of the neutron star both in longitude and latitude. An anti-correlation between residuals and X-ray flux suggests an influence of accretion rate on pulse phase, and casts doubts on the use of standard timing techniques to measure spin frequencies and torques on the neutron star.

Submitted to ApJ

References in corpus (12)

• The long-term evolution of the spin, pulse shape, and orbit of the accretion-powered millisecond pulsar SAX J1808.4-3658
• Accreting millisecond pulsar SAX J1808.4-3658 during its 2002 outburst: evidence for a receding disc
• A model for the waveform behavior of accreting millisecond pulsars: Nearly aligned magnetic fields and moving emission regions
• A decade of timing an accretion-powered millisecond pulsar: The continuing spin down and orbital evolution of SAX J1808.4-3658
• Timing of the Accreting Millisecond Pulsar XTE J1814-338
• An alternative interpretation of the timing noise in accreting millisecond pulsars
• Order in the Chaos: Spin-up and Spin-down during the 2002 Outburst of SAX J1808.4-3658
• The long-term evolution of the accreting millisecond X-ray pulsar Swift J1756.9-2508
• Spin up and phase fluctuations in the timing of the accreting millisecond pulsar XTE J1807-294
• Precise Orbital Parameters and Anomalous Phase Variations of the Accretion-powered Millisecond Pulsar XTE J1807-294
• Timing Features of the Accretion--driven Millisecond X-Ray Pulsar XTE J1807--294 in 2003 March Outburst
• Precise determination of orbital parameters in system with slowly drifting phases: application to the case of XTE J1807-294

Cited by in corpus (35)

• The Accreting Millisecond X-ray Pulsar IGR J00291+5934: Evidence for a Long Timescale Spin Evolution
• Accreting Millisecond X-Ray Pulsars
• The X-ray spectrum of the newly discovered accreting millisecond pulsar IGR J17511-3057
• Accelerated Orbital Expansion And Secular Spin Down of the Accreting Millisecond Pulsar SAX J1808.4-3658
• Search for continuous gravitational waves from 20 accreting millisecond X-ray pulsars in O3 LIGO data
• Constraints on the Mass and Radius of the Neutron Star XTE J1807-294
• Implications of burst oscillations from the slowly rotating accreting pulsar IGR 17480-2446 in the globular cluster Terzan 5
• The long-term evolution of the accreting millisecond X-ray pulsar Swift J1756.9-2508
• Spin equilibrium with or without gravitational wave emission: the case of XTE J1814-338 and SAX J1808.4-3658
• Discovery of a new accreting millisecond X-ray pulsar in the globular cluster NGC 2808
• Evidence of Fast Magnetic Field Evolution in an Accreting Millisecond Pulsar
• Discovery of an accreting millisecond pulsar in the eclipsing binary system Swift J1749.4-2807
• Radio pulse search and X-Ray monitoring of SAX J1808.4-3658: What Causes its Orbital Evolution?
• 1 Hz Flaring in the Accreting Millisecond Pulsar NGC 6440 X-2: Disk Trapping and Accretion Cycles
• Accretion onto Stars with Octupole Magnetic Fields: Matter Flow, Hot Spots and Phase Shifts
• Timing of the accreting millisecond pulsar IGR~J17511--3057
• Pulse Peak Migration during the Outburst Decay of the Magnetar SGR 1830-0645: Crustal Motion and Magnetospheric Untwisting
• Varying disc-magnetosphere coupling as the origin of pulse profile variability in SAX J1808.4-3658
• Close-in Exoplanets as Candidates of Strange Quark Matter Objects
• MAXI J1957+032: a new accreting millisecond X-ray pulsar in an ultra-compact binary
• The low luminosity behaviour of the 4U 0115+63 Be/X-ray transient
• A Deep Pulse Search in Eleven Low Mass X-Ray Binaries
• Timing of the accreting millisecond pulsar IGR J17591-2342: evidence of spin-down during accretion
• The X-ray Pulsar 2A 1822-371 as a Super Eddington source
• Discovery of pulsation dropout and turn-on during the high state of the accreting X-ray pulsar LMC X-4
• On the peculiar long-term orbital evolution of the eclipsing accreting millisecond X-ray pulsar SWIFT J1749.4-2807
• Effects of scattering in the accretion funnel on the pulse profiles of accreting millisecond pulsars
• The Peculiar Behavior of Burst Oscillations in the Accreting Millisecond X-ray Pulsar XTE J1814-338
• Recurrent low-level luminosity behaviour after a giant outburst in the Be/X-ray transient 4U 0115+63
• AstroSat timing and spectral analysis of the accretion-powered millisecond X-ray pulsar IGR J17591--2342
• Parameter constraints for accreting millisecond pulsars with synthetic NICER data
• Detection of low-luminosity X-ray pulsations from the accreting millisecond pulsar IGR J17511-3057: An ever-thinning thread between bright accretion and sub-luminous states
• Pulsar-driven Jets in Supernovae, Gamma-Ray Bursts, and the Universe
• The 2025 outburst of IGR J17511-3057: timing and spectral insights from NICER and NuSTAR
• Recurrent Instability in LMXB Accretion Disks: How Strange is GRS 1915+105?