Gamma-ray burst positions from the ASM on RXTE

Bradt, H.; Smith, D. A.

doi:10.1051/aas:1999293

Cited by 15 publications

(17 citation statements)

References 5 publications

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“…4U 0142+61 monitoring data of the PCA (2-60 keV; Jahoda et al 1996) on board the Rossi X-ray Timing Explorer (RXTE, Bradt et al 1993) were used to create a phase-coherent timing solution valid during the multiwavelength campaign (see Gavriil and Kaspi 2002, for a detailed description and use of the AXP-monitoring campaign). This ephemeris is essential for INTEGRAL timing analysis (cf., den Hartog et al 2007).…”

Section: Rossi-xtementioning

confidence: 99%

The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays

Hartog

Kuiper

Hermsen

et al. 2007

Astrophys Space Sci

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For the first time a quasi-simultaneous multiwavelength campaign has been performed on an Anomalous X-ray Pulsar from the radio to the hard X-ray band. 4U 0142+61 was an INTEGRAL target for 1 Ms in July 2005. During these observations it was also observed in the X-ray band with Swift and RXTE, in the optical and NIR with Gemini North and in the radio with the WSRT. In this paper we present the source-energy distribution. The spectral results obtained in the individual wave bands do not connect smoothly; apparently components of different origin contribute to the total spectrum. Remarkable is that the INTEGRAL hard X-ray spectrum (power-law index 0.79 ± 0.10) is now measured up to an energy of ∼230 keV with no indication of a spectral break. Extrapolation of the INTEGRAL power-law spectrum to lower energies passes orders of magnitude underneath the NIR and optical fluxes,

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Section: Rossi-xtementioning

confidence: 99%

The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays

Hartog

Kuiper

Hermsen

et al. 2007

Astrophys Space Sci

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“…PACS numbers: 97.60.Jd, 97.80.Jp, 04.80.Cc Until now about twenty LMXBs have been discoveried to exhibit kHz QPOs, include one X-ray pulsar, with the Rossi X-ray Timing Explorer (RXTE) since the early 1996, briefly after its launch [1][2][3]. The Z sources (Atoll sources), which are high (less) luminous neutron-star lowmass X-ray binaries [4], typically show four distinct types of QPOs [1].…”

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confidence: 99%

“…The relations ν H vs. ν 2 and ∆ν vs. ν 1 are plotted in Fig.1 and Fig.2, together with the well measured source samples, and it is shown that the agreement bewteen the model and the observed QPO data is quite well for the selected values of the NS mass from 1.4 to 1.8 M ⊙ , which is the solely free parameter in the Eqs. (1)(2)(3)(4)(5). From Eqs.…”

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confidence: 99%

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Quasi Periodic Oscillations in X-Ray Neutron Star and Probes of Perihelion Precession of General Relativity

Zhang

2002

Int. J. Mod. Phys. D

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We ascribe the twin kilohertz Quasi Periodic Oscillations (kHz QPOs) of X-ray spectra of Low Mass X-Ray Binaries (LMXBs) to the pseudo-Newtonian PACS numbers: 97.60.Jd, 97.80.Jp, 04.80.Cc Until now about twenty LMXBs have been discoveried to exhibit kHz QPOs, include one X-ray pulsar, with the Rossi X-ray Timing Explorer (RXTE) since the early 1996, briefly after its launch [1][2][3]. The Z sources (Atoll sources), which are high (less) luminous neutron-star lowmass X-ray binaries [4], typically show four distinct types of QPOs [1]. At present, these are the normal branch oscillation (NBO) 5 − 20 Hz, the horizontal branch oscillation (HBO) ν H 15 − 60 Hz [1], and the kHz QPOs ν 2 (ν 1 ) 200 − 1200 Hz that typically occur in pairs, upper frequency ν 2 and lower frequency ν 1 . In several Atoll sources, nearly coherent ν burst 330 − 590 Hz oscillations have also been detected during thermonuclear Type I X-ray bursts, which are considered as the spin frequency of NS or twice of them. All of these QPOs but the burst oscillation have centroid frequencies that increase with inferred mass accretion rateṀ , and are tightly correlated with each other [5,6]. In some cases, these correlations appear to depend weakly on the other properties of the sources [5,6]. For example, the frequencies ν 2 and ν 1 , as well as the frequencies ν 2 and ν H follow very similar relations in five Z sources [5,6]. However the frequency separation between the upper and the lower kHz QPOs ∆ν ≡ ν 2 − ν 1 decreases systematically with instantaneousṀ in some cases, e.g. Sco X-1 [1,7], 4U1608−52 and 4U1728−34 [1,8,9], then in the latter the observed coherent burst frequency 364 Hz is higher than its maximum ∆ν ∼ 355 Hz [1,9].A number of theoretical models have been proposed to account for the QPO phenomena in X-ray NS systems. For the high frequency of kHz QPOs and its proportional relation to the accretion rate, simply, the upper kHz QPO ν 2 is considered to originate from the Keplerian orbital frequencies at the preferred radius close to the compact object, which exhibit the inner accretion flows, however the lower kHz QPO ν 1 is attributed to the beat of such frequency with the stellar spin ν s [10]. Recently, the general relativistic effects are paid much attetion to account for kHz QPOs [11,12], which can explain the varied kHz QPOs separation ∆ν. Then the varied ∆ν seems to exclude the simple beat explanation for kHz QPOs [1,6], which predicts a constant frequency separation. However, it is also a common phenomenon for the separation ∆ν to be approximately constant. The range of ∆ν is also quite narrow across different sources (∆ν ≈ 250 − 360 Hz) with a nearly coherent frequency of ν burst ≈ 330 − 590 Hz. In some cases (such as 4U 1702-43 and KS 1731-260) the burst frequency is consistent, to within the errors, with the frequency separation ∆ν, or twice its value 2∆ν. So the approximately constant separation in some sources seems also to make the purely GR precession model in difficulty. Although many other viable new ideas are also propo...

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“…The implications for our techniques are explained where appropriate below (and see Appendix). Calibration is undertaken by the ASM/RXTE team and the processed data are freely accessible on their website 2 (Bradt et al 2001). The RXTE counts are not directly proportional to luminosity, so the exact relationship between these two quantities would have to be accounted for in any model.…”

Section: Introductionmentioning

confidence: 99%

Characterising Anomalous Transport in Accretion Disks from X-ray Observations

Greenhough¹,

Chapman²,

Chaty³

et al.

Statistical Challenges in Astronomy

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Abstract. Whilst direct observations of internal transport in accretion disksare not yet possible, measurement of the energy emitted from accreting astrophysical systems can provide useful information on the physical mechanisms at work. Here we examine the unbroken multi-year time variation of the total X-ray flux from three sources: Cygnus X-1, the microquasar GRS1915+105, and for comparison the nonaccreting Crab nebula. To complement previous analyses, we demonstrate that the application of advanced statistical methods to these observational time-series reveals important contrasts in the nature and scaling properties of the transport processes operating within these sources. We find the Crab signal resembles Gaussian noise; the Cygnus X-1 signal is a leptokurtic random walk whose self-similar properties persist on timescales up to three years; and the GRS1915+105 signal is similar to that from Cygnus X-1, but with self-similarity extending possibly to only a few days. This evidence of self-similarity provides a robust quantitative characterisation of anomalous transport occuring within the systems.

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Gamma-ray burst positions from the ASM on RXTE

Cited by 15 publications

References 5 publications

The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays

The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays

Quasi Periodic Oscillations in X-Ray Neutron Star and Probes of Perihelion Precession of General Relativity

Characterising Anomalous Transport in Accretion Disks from X-ray Observations

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