2006/11/10 by Sergei Nayakshin
Physics and Astronomy · #Accretion (finance) #Accretion disc #Active galactic nucleus #Anisotropy #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Flare #Flux (metallurgy) #Galaxy #Magnetic field #Magnetic flux #Optics #Physics #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1111/j.1745-3933.2007.00279.x
published as Mon.Not.Roy.Astron.Soc.Lett.376:L25-L28,2007 · submitted to MNRAS Letters; 3 pages
arxiv created 2006/11/10 · openalex publication_date 2007/02/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Abstract Straightforward models of X-ray reflection in the inner region of accretion discs predict that the primary X-ray flux and the flux reflected off the surface of the disc should vary together, albeit with a short light traveltime delay. Most of the observations, however, show that the X-ray flux can vary while the reflected features remain constant. Here we propose a simple explanation for this. In all likelihood, the emission of a moderately optically thick magnetic flare atop an accretion disc is anisotropic. A constant energy release rate in a flare will appear to produce a variable X-ray flux as the flare rotates with the accretion disc anchoring the magnetic tube. The reflector, on the other hand, receives a constant X-ray flux from the flare. Since the reflected emission is azimuthally symmetric, the observer will see a roughly constant reflected flux (neglecting relativistic effects). The model does not produce quasi-periodic oscillations if magnetic flux tubes are sheared out faster than they complete one orbit.