Extremal energy shifts of radiation from a ring near a rotating black hole

Abstract

Radiation from a narrow circular ring shows a characteristic double-horn profile dominated by photons having energy around the maximum or minimum of the allowed range, i.e. near the extremal values of the energy shift. The energy span of a spectral line is a function of the ring radius, black hole spin, and observer's view angle. We describe a useful approach to calculate the extremal energy shifts in the regime of strong gravity. Then we consider an accretion disk consisting of a number of separate nested annuli in the equatorial plane of Kerr black hole, above the innermost stable circular orbit (ISCO). We suggest that the radial structure of the disk emission could be reconstructed using the extremal energy shifts of the individual rings deduced from the broad wings of a relativistic spectral line.

9 pages, 5 figures, ApJ accepted

References in corpus (4)

• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• Broad iron K-alpha emission lines as a diagnostic of black hole spin
• Relativistic spectral features from X-ray illuminated spots and the measure of the black hole mass in AGN
• Where is the Radiation Edge in Magnetized Black Hole Accretion discs?