Timing an Accreting Millisecond Pulsar: Measuring the Accretion Torque in IGR J00291+5934
- Autori: BURDERI, L; DI SALVO, T; LAVAGETTO, G; MENNA, MT; PAPITTO, A; RIGGIO, A; IARIA, R; D'ANTONA, F; ROBBA, N; STELLA, L
- Anno di pubblicazione: 2007
- Tipologia: Articolo in rivista (Articolo in rivista)
- Parole Chiave: pulsars : general; pulsars : individual (IGR J00291+5934); stars : magnetic fields; stars : neutron; X-rays : binaries
- OA Link: http://hdl.handle.net/10447/17684
Abstract
We performed a timing analysis of the fastest accreting millisecond pulsar IGR J00291+5934 using RXTE data taken during the outburst of 2004 December. 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 are able to study, for the first time in this class of sources, the spin-up of a millisecond pulsar 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.