منابع مشابه
Superorbital variability of X-ray and radio emission of Cyg X-1 – II. Dependence of the orbital modulation on the superorbital phase
We discover a pronounced dependence of the strength of the soft X-ray orbital modulation in Cyg X-1 in the hard state on its superorbital phase. We find our results can be well modelled as orbital-phase dependent X-ray absorption in an accretion bulge, located at the accretion disc edge close to the companion but displaced from the line connecting the stars by about 25◦ and in the case when the...
متن کاملSuperorbital variability of X-ray and radio emission of Cyg X-1 – II. Dependence of the orbital modulation and spectral hardness on the superorbital phase
We discover a pronounced dependence of the strength of the soft X-ray orbital modulation and the spectral hardness in Cyg X-1 in the hard state on its superorbital phase. We find our results can be well modelled as a combination of two effects: the precession of the accretion disc (which appears to cause the superorbital flux modulation) and the orbital-phase dependent X-ray absorption in an ac...
متن کاملOrbital and superorbital variability and their coupling in X-ray binaries
We review X-ray flux modulation from X-ray binaries on time scales corresponding to the orbital period and those at longer time scales (so called superorbital). Those modulations provide a powerful tool to constrain geometry of the accretion flow. The most common cause of the superorbital variability appears to be precession. We then discuss two specific examples of discoveries of a coupling be...
متن کاملThe superorbital variability and triple nature of the X - ray source 4 U 1820 – 303
We perform a comprehensive analysis of the superorbital modulation in the ultracompact Xray source 4U 1820–303, consisting of a white dwarf accreting onto a neutron star. Based on RXTE data, we measure the fractional amplitude of the source superorbital variability (with a ∼170-d quasi-period) in the folded and averaged light curves, and find it to be by a factor of ∼2. As proposed before, the ...
متن کاملSuperorbital variability of X-ray and radio emission of Cyg X-1. I. Emission anisotropy of precessing sources
We study theoretical interpretations of the ∼150-d (superorbital) modulation observed in Xray and radio emission of Cyg X-1 in the framework of models connecting this phenomenon to precession. Precession changes the orientation of the emission source (either disc or jet) relative to the observer. This leads to emission modulation due to an anisotropic emission pattern of the source or orientati...
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ژورنال
عنوان ژورنال: Science
سال: 2013
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.341.6147.696-a