An accreting millisecond pulsar with black hole-like X-ray variability: IGR J00291+5934

Abstract

IGR J00291+5934 is one of the seven accreting millisecond pulsars (AMPs) discovered so far. We report on the aperiodic timing and color analysis of its X-ray flux, using all the RXTE observations of the 2004 outburst. Flat-top noise and two harmonically related quasi-periodic oscillations, all of them at very low frequencies (0.01-0.1 Hz), were present in the power spectra during most of the outburst as well as a very high fractional variability (~50%). These properties are atypical not only for AMPs but also for neutron star low-mass X-ray binaries (LMXBs) in general. There are instead some remarkable similarities with the variability observed in black hole systems, reinforcing the connections between these two types of LMXB, as well as some interesting differences. We note finally that the results of this paper are difficult to reconcile with interpretations where any break frequency of power density spectra scales inversely with the mass of the central object at an accuracy sufficient to distinguish between the masses of neutron stars and black holes in LMXBs.

Accepted by The Astrophysical Journal. Scheduled for ApJ May 1, 2007, v660n1 issue. Minor changes according to referee's comments

References in corpus (13)

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• Timing an Accreting Millisecond Pulsar: Measuring the Accretion Torque in IGR J00291+5934
• The Island state of the Atoll Source 4U 1820--30
• Chandra observations of the millisecond X-ray pulsar IGR J00291+5934 in quiescence
• Discovery of the INTEGRAL X/Gamma-ray transient IGR J00291+5934: a Comptonised accreting ms pulsar ?
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• A Double Outburst from IGR J00291+5934: Implications for Accretion Disk Instability Theory
• The influence of spin on jet power in neutron star X-ray binaries
• Spectral and timing properties of the accreting X-ray millisecond pulsar IGR J17511-3057
• Observations of the 599 Hz Accreting X-ray Pulsar IGR J00291+5934 during the 2004 Outburst and in Quiescence
• Discovery of an accreting millisecond pulsar in the eclipsing binary system Swift J1749.4-2807
• Spectral and timing properties of IGR J00291+5934 during its 2015 outburst
• Low-frequency QPO from the 11 Hz accreting pulsar in Terzan 5: not frame dragging
• An X-ray view of the very faint black hole X-ray transient Swift J1357.2-0933 during its 2011 outburst
• The Double-Peaked 2008 Outburst of the Accreting Milli-Second X-ray Pulsar, IGR J00291+5934
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• Two new bursting neutron star low-mass X-ray binaries: Swift J185003.2-005627 and Swift J1922.7-1716
• The stochastic X-ray variability of the accreting millisecond pulsar MAXI J0911-655
• Broad iron emission line and kilohertz quasi-periodic oscillations in the neutron star system 4U 1636-53
• Possible twin kHz Quasi Periodic Oscillations in the accreting millisecond X-ray Pulsar IGR J17511-3057
• X-ray variability of transitional millisecond pulsars: a faint, stable and fluctuating disk
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