Open AccessThe influence of central black holes on gravitational lenses
Author(s) -
Mao Shude,
Witt Hans J.,
Koopmans Leon V. E.
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04143.x
Subject(s) - physics , black hole (networking) , astrophysics , stellar black hole , supermassive black hole , binary black hole , spin flip , schwarzschild radius , radius , intermediate mass black hole , rotating black hole , gravitational lens , galaxy , astronomy , accretion (finance) , gravitational wave , redshift , routing (electronic design automation) , computer security , computer science , link state routing protocol , computer network , routing protocol
Recent observations indicate that many if not all galaxies host massive central black holes. In this paper we explore the influence of black holes on the lensing properties. We model the lens as an isothermal ellipsoid with a finite core radius plus a central black hole. We show that the presence of the black hole substantially changes the critical curves and caustics. If the black hole mass is above a critical value, then it will completely suppress the central images for all source positions. Realistic central black holes are likely to have masses below this critical value. Even in such subcritical cases, the black hole can suppress the central image when the source is inside a zone of influence, which depends on the core radius and black hole mass. In the subcritical cases, an additional image may be created by the black hole in some regions, which for some radio lenses may be detectable with high‐resolution and large dynamic range VLBI maps. The presence of central black holes should also be taken into account when one constrains the core radius from the lack of central images in gravitational lenses.