Phenomenology of the 35-Day Cycle of Hercules X-1

Шакура, Н. И.; Ketsaris, N. A.; Постнов, К. А.; Прохоров, М. Е.

doi:10.1007/978-94-010-0548-7_24

Cited by 27 publications

(58 citation statements)

References 8 publications

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“…1). The turn-on of the source can be considered as the egress from an anomalous dip at φ orb ∼ 0.5 (according to the model of Shakura et al (1999) the source is partially screened by the outer accretion disk rim in both cases: during the turn-on of the source and during anomalous dips). Thus, the light curve obtained with INTEGRAL contains three pre-eclipse dips and one anomalous dip.…”

Section: X-ray Dipsmentioning

confidence: 99%

“…According to the model of Shakura et al (1999) and Klochkov et al (2006) (which we adopt in this work), most of the X-ray dips are produced by the occultation of the X-ray source by the cold matter in the accretion stream which moves out of the system's orbital plane. If the stream is not homogeneous but consists of "blobs" of material then the source will be screened during some time intervals within a dip.…”

Section: Absorption During X-ray Dipsmentioning

confidence: 99%

“…Being part of a low mass X-ray binary it shows strong variability on very different time scales: the 1.24 s spin period of the neutron star, the 1.7 d binary period, the 35 d period of precession of the warped and tilted accretion disk (Gerend & Boynton 1976;Shakura et al 1999;Ketsaris et al 2000), and the 1.65 d period of the pre-eclipse dips (Giacconi et al 1973;Tananbaum et al 1972). Due to the high orbital inclination of the system (i > 80…”

Section: Introductionmentioning

confidence: 99%

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INTEGRAL observations of Hercules X-1

Klochkov¹,

Staubert²,

Постнов³

et al. 2008

A&A

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Aims. We investigate the X-ray spectral and timing properties of the accreting X-ray pulsar Her X-1 observed with the INTEGRAL satellite in July-August 2005. Methods. The data analyzed in this work cover a substantial part of one main-on state of the source. The short time scale pulse period development is measured. X-ray pulse profiles for different energy ranges and time intervals are constructed. Pulse-averaged and pulse-phase resolved broad band X-ray spectra are studied. Spectral changes during X-ray dips are explored.Results. The X-ray pulse profiles are found to change significantly during the period of observations. For the first time a strong spinup is measured within one 35 d cycle. Spectral characteristics observed during the X-ray dips are consistent with their interpretation as being due to partial covering as has been reported by several authors. The fundamental cyclotron absorption line is firmly observed in both pulse-averaged and pulse-phase resolved X-ray spectra. The energy, width, and the depth of the line are found to vary significantly with pulse phase.

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Section: X-ray Dipsmentioning

confidence: 99%

Section: Absorption During X-ray Dipsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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INTEGRAL observations of Hercules X-1

Klochkov¹,

Staubert²,

Постнов³

et al. 2008

A&A

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“…The inner and outer parts of the warped disk start screening the central X-ray source at the different times (see e.g. Shakura et al 1999, and references therein). The disk in Her X-1 precesses as a whole in the direction opposite to the orbital revolution, so the inner parts of the disk appear to lead the outer parts in the precessional motion.…”

Section: Viscous Time Scale In the Accretion Diskmentioning

confidence: 99%

Broad band variability of SS433: accretion disk at work?

Revnivtsev

Fabrika

Abolmasov³

et al. 2006

A&A

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We present broad band power spectra of variations of SS433 in radio, optical and X-ray spectral bands. We show that at frequencies lower than 10 −5 Hz the source demonstrates the same variability pattern in all these bands. The broad band power spectrum can be fitted by one power law down to frequencies ∼10 −7 Hz with flattening afterwards. Such a flattening means that on time scales longer than ∼10 7 s the source variability becomes uncorrelated. This naturally leads to the appearance of quasi-poissonian flares in the source light curve, which have been regularly observed in radio and optical spectral bands. The radio flux power spectrum appears to have a second break at Fourier frequencies ∼10 −5 Hz which can be caused by the smearing of the intrinsic radio variability on timescale of the light-crossing time of the radio emitting region. We find a correlation of the radio and optical fluxes of SS433 and the radio flux is delayed by about ∼2 days with respect to the optical one. Power spectra of optical and X-ray variabilities continue with the same power law from 10 −7 Hz up to ∼0.01−0.05 Hz. The broad band power spectrum of SS433 can be interpreted in terms of self-similar accretion rate modulations in the accretion disk proposed by Lyubarskii (1997, MNRAS, 292, 679) and elaborated by Churazov et al. (2001, MNRAS, 321, 759). We discuss a viscous time-scale in the accretion disk of SS433 with reference to the observed broad band power spectrum.

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“…For the 35 day on-off cycle, the proposed geometries include, precession of a slave-disk, warp disk etc. (Roberts 1974;Petterson 1975;Pringle 1996;Shakura et al 1999). A reduced accretion and a reduction in the inclination of the accretion disk has been proposed to be the cause for the ALS by Coburn et al (2000).…”

Section: Discussionmentioning

confidence: 99%

Hard X-ray behaviour of Her X-1 during second main-on after the anomalous low state

Manchanda

2003

A&A

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Abstract. The binary X-ray pulsar Her X-1 shows a variety of time variations both in luminosity and its pulse features. For the first time an about 600 days long anomalous low state was seen in the light curve of ASM on board RXTE during the period MJD 51200-51800. We observed the source in the 20-200 keV energy band during its second main-on in the post anomalous state on November 21, 2000. The source was found to be extremely bright at high energies and a total of 26 000 photons from the source were detected during the 35 min snapshot observation. The cyclotron absorption line at ∼34 keV and its second harmonics were clearly detected in the data. We present the spectral details and discuss its implication in terms of the geometrical properties of the source.

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Phenomenology of the 35-Day Cycle of Hercules X-1

Cited by 27 publications

References 8 publications

INTEGRAL observations of Hercules X-1

INTEGRAL observations of Hercules X-1

Broad band variability of SS433: accretion disk at work?

Hard X-ray behaviour of Her X-1 during second main-on after the anomalous low state

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