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Timing an Accreting Millisecond Pulsar: Measuring the Accretion Torque in IGR J00291+5934

L. Burderi·T. Di Salvo·A. Riggio·M. T. Menna·G. Lavagetto·A. Papitto·R. Iaria·N. R. Robba·L. Stella
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Abstract

We present here a timing analysis of the fastest accreting millisecond pulsar IGR J00291+5934 using RXTE data taken during the outburst of December 2004. We corrected the arrival times of all the events for the orbital (Doppler) effects and performed a timing analysis of the resulting phase delays. In this way we find a clear parabolic trend of the pulse phase delays showing that the pulsar is spinning up as a consequence of accretion torques during the X-ray outburst. The accretion torque gives us for the first time an independent estimate of the mass accretion rate onto the neutron star, which can be compared with the observed X-ray luminosity. We also report a revised value of the spin period of the pulsar.

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L. Burderi, T. Di Salvo, A. Riggio, M. T. Menna, G. Lavagetto, A. Papitto, R. Iaria, N. R. Robba, L. Stella. 2005-09-08. Timing an Accreting Millisecond Pulsar: Measuring the Accretion Torque in IGR J00291+5934. https://doi.org/10.1086/510659

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