SIMBAD references

We present 6.4 keV iron Kα fluorescent line profiles predicted for a relativistic black hole accretion disk in the presence of a spiral motion in Kerr geometry, the work extended from earlier literature motivated by recent magnetohydrodynamic (MHD) simulations. The velocity field of the spiral motion, superposed on the background Keplerian flow, results in a complicated redshift distribution in the accretion disk. An X-ray source attributed to a localized flaring region on the black hole symmetry axis illuminates the iron in the disk. The emissivity form becomes very steep because of the light-bending effect from the primary X-ray source to the disk. The fluorescent line is calculated for various spiral waves with different X-ray source height. It is found, regardless of the source height, in the predicted broad-line profile that (1) a ubiquitous multiple peak along with a classical double-peaked structure generally appears; (2) such a multiple peak can be categorized into two types, sharp subpeaks and periodic spiky peaks; (3) a tightly packed spiral wave tends to produce more spiky multiple peaks, whereas (4) a spiral wave with a larger amplitude seems to generate more sharp subpeaks; (5) the effect seems to be less significant when the spiral wave is centrally concentrated; and (6) the line shape may show a drastic change (forming a double-peaked, triple-peaked, or multiple-peaked feature) as the spiral wave rotates with the disk (phase-dependent line). Our results emphasize that around a rapidly rotating black hole an extremely redshifted iron line profile with a noticeable spikelike feature can be realized in the presence of the spiral wave. Future X-ray observations, from Astro-E2, for example, will have sufficient spectral resolution for testing our spiral-wave model, which exhibits unique spikelike features. Furthermore, they may be able to allow us to identify the characteristics of the spiral wave occurring in the innermost accretion disk.