منابع مشابه
Outbursts of Irradiated Accretion Discs
I solve analytically the viscous evolution of a self–irradiated accretion disc, as seen during outbursts of soft X–ray transients. The solutions predict steep power–law X– ray decays LX ∼ (1 + t/tvisc) , changing to LX ∼ (1 − t/t ′ visc ) at late times, where tvisc, t ′ visc are viscous timescales. These forms closely resemble the approximate exponential and linear decays inferred by King and R...
متن کاملADAFs, accretion discs and outbursts in compact binaries
I discuss the status of the Soft X-ray Transient model. First, I discuss and then compare with observations the assumption that the geometrically thin disc evaporates into an ADAF. Second, I address the problems created by the recent determinations of the distance to SS Cyg, according to which the Disc Instability Model does not apply to this famous dwarf-nova, thus casting doubt on the applica...
متن کاملIonization structure and Fe Kα energy for irradiated accretion discs
We study the radial ionization structure at the surface of an X-ray illuminated accretion disc. We plot the expected iron Kα line energy as a function of the Eddington ratio and of the distance of the emitting matter from the central source, for a non-rotating and a maximally rotating black hole. We compare the predicted disc line energies with those measured in an archival sample of active gal...
متن کاملAccretion-powered Millisecond Pulsar Outbursts
The population of accretion-powered millisecond pulsars (AMSPs) has grown rapidly over the last four years, with the discovery of six new examples to bring the total sample to seven. While the first six discovered are transients active for a few weeks every two or more years, the most recently-discovered source HETE J1900.1−2455, has been active for more than 8 months. We summarise the transien...
متن کاملModelling magnetised accretion discs
Some recent results are reviewed that lead us now to believe that accretion discs are basically always magnetised. The main components are Balbus-Hawley and Parker instabilities on the one hand and a dynamo process on the other. A mechanical model for the Balbus-Hawley instability is presented and analysed quantitatively. Three-dimensional simulations are discussed, especially the resulting mag...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1998
ISSN: 0035-8711,1365-2966
DOI: 10.1046/j.1365-8711.1998.01652.x