Study of the accretion torque during the 2014 outburst of the X-ray pulsar GRO J1744-28

Abstract

We present the spectral and timing analysis of the X-ray pulsar GRO J1744-28 during its 2014 outburst using data collected with the X-ray satellites Swift, INTEGRAL, Chandra, and XMM-Newton. We derived, by phase-connected timing analysis of the observed pulses, an updated set of the source ephemeris. We were also able to investigate the spin-up of the X-ray pulsar as a consequence of the accretion torque during the outburst. Relating the spin-up rate and the mass accretion rate as $\dot{\nu }\propto {\dot{M}}^{\beta }$, we fitted the pulse phase delays obtaining a value of $\beta =0.96(3)$. Combining the results from the source spin-up frequency derivative and the flux estimation, we constrained the source distance to be between 3.4-4.1 kpc, assuming a disc viscous parameter $\alpha$ to be in the range 0.1-1. Finally, we investigated the presence of a possible spin-down torque by adding a quadratic component to the pulse phase delay model. The marginal statistical improvement of the updated model does not allow us to firmly confirm the presence of this component.

12 pages, 5 figures. Accepted for publication in MNRAS

References in corpus (7)

• Accretion disc viscosity: how big is alpha?
• High-Resolution X-Ray Spectroscopy of the Bursting Pulsar GRO J1744-28
• Can disk-magnetosphere interaction models and beat frequency models for quasi-periodic oscillation in accreting X-ray pulsars be reconciled?
• Timing an Accreting Millisecond Pulsar: Measuring the Accretion Torque in IGR J00291+5934
• GRO J1744-28: an intermediate B-field pulsar in a low mass X-ray binary
• Testing Rate Dependent corrections on timing mode EPIC-pn spectra of the accreting Neutron Star GX 13+1
• Systematic Uncertainties in the Spectroscopic Measurements of Neutron-Star Masses and Radii from Thermonuclear X-ray Bursts. III. Absolute Flux Calibration

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