The Nature of the Fluctuations Preceding the Giant Bursts in the Bursting Pulsar GRO J1744−28

Cannizzo, J. K.

doi:10.1086/304150

Cited by 12 publications

(11 citation statements)

References 18 publications

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“…In this case, the radiation pressure is comparable to the gas pressure around the inner disk radius (i.e., the magnetospheric radius), resulting in a viscous instability with slightly increased mass accretion (e.g., Cannizzo 1996Cannizzo , 1997. Because the instability develops near the inner edge of the accretion disk, it has an advantage in explaining bursts/flares with a short recurrence time.…”

Section: Discussionmentioning

confidence: 99%

SMC X-1 as an Intermediate-Stage Flaring X-Ray Pulsar

Eikenberry

Wasserman

2003

The Astrophysical Journal

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We present Rossi X-Ray Timing Explorer observations of the X-ray pulsar SMC X-1. The source is highly variable on short timescales (!1 hr), exhibiting apparent flares occupying a significant fraction (∼3%) of the total observing time. The flares seem to occur over all binary orbital phases and correlate with the overall variability in the light curve. We find a total of 323 discrete flares having a mean FWHM of ∼18 s. The detailed properties of SMC X-1 do not vary significantly between the flares and the normal state, suggesting that the flare may be an extension of the normal state persistent emission with increased accretion rates. The flares resemble type II X-ray bursts from GRO J1744Ϫ28. We discuss the origin of the SMC X-1 flares in terms of a viscous instability near the inner edge of the accretion disk around a weakly magnetized X-ray pulsar and find this is consistent with the interpretation that SMC X-1 is in fact an intermediate-stage source like GRO J1744Ϫ28.

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Section: Discussionmentioning

confidence: 99%

SMC X-1 as an Intermediate-Stage Flaring X-Ray Pulsar

Eikenberry

Wasserman

2003

The Astrophysical Journal

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“…Interestingly, the variability at low Fourier frequencies (below ∼ 10 Hz) in GRO J1744−28 is suppressed at high mass accretion rates and the suppression starts as soon as type-II bursts start to appear in the light curve of the source. Note that numerical simulations of accretion instability of RPD part of a disk (Cannizzo 1997) show an appearance of QPOs, which finally end up in a type-II burst. Typical time scale of the oscillations is t osc ∼ 10 − 20 s. We suggest that these oscillations suppress the fluctuations of the mass accretion rate at frequencies below 1/t osc originating from the outer parts of the accretion disk.…”

Section: Transfer Functionmentioning

confidence: 96%

“…At the same time, it has been shown that the aperiodic variability by itself can principally stabilize RPD accretion flow(Suková & Janiuk 2016). See alsoCannizzo (1996Cannizzo ( , 1997 discussing the bursts of GRO J1744−28.…”

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confidence: 98%

Evidence for the radiation-pressure dominated accretion disk in bursting pulsar GRO J1744−28 using timing analysis

Mönkkönen

Tsygankov

Mushtukov

et al. 2019

A&A

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The X-ray pulsar GRO J1744−28 is a unique source which shows both pulsations and type-II X-ray bursts, allowing studies of the interaction of the accretion disk with the magnetosphere at huge mass accretion rates exceeding 10 19 g s −1 during its super-Eddington outbursts. The magnetic field strength in the source, B ≈ 5 × 10 11 G, is known from the cyclotron absorption feature discovered in the energy spectrum around 4.5 keV. Here, we explore the flux variability of the source in context of interaction of its magnetosphere with the radiation-pressure dominated accretion disk. Particularly, we present the results of the analysis of noise power density spectra (PDS) using the observations of the source in 1996-1997 by the Rossi X-ray Timing Explorer (RXTE). Accreting compact objects commonly exhibit a broken power-law shape of the PDS with a break corresponding to the Keplerian orbital frequency of matter at the innermost disk radius. The observed frequency of the break can thus be used to estimate the size of the magnetosphere. We found, however, that the observed PDS of GRO J1744−28 differs dramatically from the canonical shape. Furthermore, the observed break frequency appears to be significantly higher than what is expected based on the magnetic field estimated from the cyclotron line energy. We argue that these observational facts can be attributed to the existence of the radiation-pressure dominated region in the accretion disk at luminosities above ∼2×10 37 erg s −1 . We discuss a qualitative model for the PDS formation in such disks, and show that its predictions are consistent with our observational findings. The presence of the radiation-pressure dominated region can also explain the observed weak luminosity-dependence of the inner radius, and we argue that the small inner radius can be explained by a quadrupole component dominating the magnetic field of the neutron star.

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“…Cannizzo (1996) showed that these oscillations eventually lead to a Lightman-Eardley instability (Lightman, Eardley, 1974), which Cannizzo (1996) considered to be the cause of Type II bursts. Cannizzo (1997) further showed that the characteristic QPO frequency can be reproduced by a selection of parameters. Abramowicz et al (1995) suggested that low-frequency QPOs in some XBs (including those of the Rapid Burster) and black-hole candidates can be produced via dissipation of energy in the coronal region above the accretion disk.…”

Section: Comparison With Qpos In Xbsmentioning

confidence: 94%

Photometry of the 1991 Superoutburst of EF Pegasi: Super-Quasi-Periodic Oscillations with Rapidly Decaying Periods

Katô¹

2002

Publications of the Astronomical Society of Japan

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We observed the 1991 October outburst of EF Peg. Prominent superhumps with a period of 0.08705(1) d were observed, qualifying EF Peg as a being long-period SU UMa-type dwarf nova. The superhump period showed a monotonous decrease during the superoutburst, which makes a contrast to the virtually zero period change observed during the 1997 superoutburst of the same object. Large-amplitude, and highly coherent quasi-periodic oscillations (super-QPOs) were observed on October 18, when superhumps were still growing in amplitude. Most strikingly, the QPOs showed a rapid decrease of the period from 18 m to 6.8 m within the 3.2-hr observing run. Such a rapid change in the period has not been observed in any class of QPOs in cataclysmic variables. We propose a hypothesis that the rapid decrease of the QPO period reflects the rapid removal of the angular momentum from an orbiting blob in the accretion disk, via the viscosity in a turbulent disk. A brief comparison is given with the QPOs in Xray binaries, some of which are known to show a similar rapid decrease in the periods.

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The Nature of the Fluctuations Preceding the Giant Bursts in the Bursting Pulsar GRO J1744−28

Cited by 12 publications

References 18 publications

SMC X-1 as an Intermediate-Stage Flaring X-Ray Pulsar

SMC X-1 as an Intermediate-Stage Flaring X-Ray Pulsar

Evidence for the radiation-pressure dominated accretion disk in bursting pulsar GRO J1744−28 using timing analysis

Photometry of the 1991 Superoutburst of EF Pegasi: Super-Quasi-Periodic Oscillations with Rapidly Decaying Periods

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