X-Ray Line Profile Variations during Quasar Microlensing

0496083 - ASÚ 2019 RIV US eng J - Journal Article
Ledvina, L. - Heyrovský, D. - Dovčiak, Michal
X-Ray Line Profile Variations during Quasar Microlensing.
Astrophysical Journal. Roč. 863, č. 1 (2018), č. článku 66. ISSN 0004-637X. E-ISSN 1538-4357
R&D Projects: GA ČR GB14-37086G; GA MŠMT(CZ) LTAUSA17095
Institutional support: RVO:67985815
Keywords : accretion disks * black hole physics * gravitational lensing
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 5.580, year: 2018

We explore the effect by simulating a microlensing caustic crossing a spatially resolved model of emission from a thin accretion disk around a Kerr black hole. We demonstrate the sequence of spectral changes during the event, in particular the appearance of additional peaks and edges in the line profile due to microlensing. We trace the origin of these features to points on the disk, at which the total energy shift (g-factor) contours are tangent to the caustic. Contours tangent from the inner side of the caustic generate peaks, while those tangent from its outer side generate edges. We derive analytical shapes of the generated features and map the peak strength as a function of position of the tangent point on the disk. Since the features are determined by the positional geometry of the caustic relative to the g-factor contours, the same type of behavior can be expected in a much broader range of emission models. The sequence of line profile changes thus serves as a sensitive probe of the geometry and physics of the innermost region of the quasar accretion disk.
Permanent Link: http://hdl.handle.net/11104/0288906