The Peculiar Behavior of Burst Oscillations in the Accreting Millisecond X-ray Pulsar XTE J1814-338
arXiv:2112.00612 · doi:10.1093/mnras/stab3536
Abstract
Accreting millisecond X-ray pulsars (AMXPs) show burst oscillations during thermonuclear explosions of the accreted plasma which are markedly different from those observed in non-pulsating low mass X-ray binaries. The AMXP XTE J1814-338 is known for having burst oscillations that are phase locked (constant phase difference) and coincident with the accretion powered pulsations during all its thermonuclear bursts but the last one. In this work we use a coherent timing analysis to investigate this phenomenon in more detail and with higher time resolution than was done in the past. We confirm that the burst oscillation phases are, on average, phase locked to the accretion powered pulsations. However, they also display moderate (<~ 0.1 cycles) drifts during each individual burst, showing a repeating pattern that is consistently observed according to the thermonuclear burst phase (rise, peak, tail). Despite the existence of these drifting patterns, the burst oscillation phases somehow are able to average out at almost the exact position of the accretion powered pulsations. We provide a kinematic description of the phenomenon and review the existing models in the literature. The phenomenon remains without a clear explanation, but we can place important constraints on the thermonuclear burst mechanism. In particular, the observations imply that the ignition point of the thermonuclear burst occurs close to the foot of the accretion column. We speculate that the burning fluid expands in a backward tilted accretion column trapped by the magnetic field, while at the same time the burning flame covers the surface.
arXiv commentAccepted for publication by MNRAS
References in corpus (34)
- Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
- Calibration of the Rossi X-ray Timing Explorer Proportional Counter Array
- Nuclear-Powered Millisecond Pulsars and the Maximum Spin Frequency of Neutron Stars
- On the Nature of the X-ray Emission from the Accreting Millisecond Pulsar SAX J1808.4-3658
- Thermonuclear burst oscillations
- The long-term evolution of the spin, pulse shape, and orbit of the accretion-powered millisecond pulsar SAX J1808.4-3658
- Propagation of thermonuclear flames on rapidly rotating neutron stars: extreme weather during type I X-ray bursts
- Rotational Evolution During Type I X-Ray Bursts
- Evidence for accretion rate change during type I X-ray bursts
- X-ray Bursts from the Accreting Millisecond Pulsar XTE J1814-338
- Physics of accretion in the millisecond pulsar XTE J1751-305
- R-Modes on Rapidly Rotating, Relativistic Stars: I. Do Type-I Bursts Excite Modes in the Neutron-Star Ocean?
- Constraints on Neutron Star Parameters from Burst Oscillation Light Curves of the Accreting Millisecond Pulsar XTE J1814-338
- A model for the waveform behavior of accreting millisecond pulsars: Nearly aligned magnetic fields and moving emission regions
- Accreting Millisecond X-Ray Pulsars
- Magnetohydrodynamic Shallow Water Waves: Linear Analysis
- Timing of the Accreting Millisecond Pulsar XTE J1814-338
- An alternative interpretation of the timing noise in accreting millisecond pulsars
- Implications of burst oscillations from the slowly rotating accreting pulsar IGR 17480-2446 in the globular cluster Terzan 5
- Type I X-ray bursts and burst oscillations in the accreting millisecond X-ray pulsar IGR J17511-3057
- Analysis of variability in the burst oscillations of the accreting millisecond pulsar XTE J1814-338
- Spin equilibrium with or without gravitational wave emission: the case of XTE J1814-338 and SAX J1808.4-3658
- Accretion torques and motion of the hot spot on the accreting millisecond pulsar XTE J1807-294
- Neutron Star Crustal Interface Waves
- The energy dependence of burst oscillations from the accreting millisecond pulsar XTE J1814-338
- Accretion heated atmospheres of X-ray bursting neutron stars
- Coherence of burst oscillations and accretion-powered pulsations in the accreting millisecond pulsar XTE J1814-338
- Evolution of the bursting-layer wave during a Type 1 X-ray burst
- Latitudinal Shear Instabilities during Type I X-ray Bursts
- Effects of thermonuclear X-ray bursts on non-burst emissions in the soft state of 4U 1728--34
- Three-dimensional instability of flame fronts in type I X-ray bursts
- X-ray burst ignition location on the surface of accreting X-ray pulsars: Can bursts preferentially ignite at the hotspot?
- Torsional Magnetic Oscillations in Type I X-Ray Bursts
- Breaking the AMSP mould: the increasingly strange case of HETE J1900.1-2455