Light deflection, lensing, and time delays from gravitational potentials and Fermat's principle in the presence of a cosmological constant

Journal Article · Sat Nov 15 04:00:00 EST 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.78.103006· OSTI ID:21250874

Ishak, Mustapha ^[1]

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1. Department of Physics, University of Texas at Dallas, Richardson, Texas 75083 (United States)

The contributions of the cosmological constant to the deflection angle and the time delays are derived from the integration of the gravitational potential as well as from Fermat's principle. The findings are in agreement with recent results using exact solutions to Einstein's equations and reproduce precisely the new {lambda} term in the bending angle and the lens equation. The consequences on time-delay expressions are explored. While it is known that {lambda} contributes to the gravitational time delay, it is shown here that a new {lambda} term appears in the geometrical time delay as well. Although these newly derived terms are perhaps small for current observations, they do not cancel out as previously claimed. Moreover, as shown before, at galaxy cluster scale, the {lambda} contribution can be larger than the second-order term in the Einstein deflection angle for several cluster lens systems.

• OSTI ID: 21250874
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 10 Vol. 78; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
99 GENERAL AND MISCELLANEOUS
COSMOLOGICAL CONSTANT
EINSTEIN FIELD EQUATIONS
EXACT SOLUTIONS
FERMAT PRINCIPLE
GALAXY CLUSTERS
GRAVITATIONAL FIELDS
GRAVITATIONAL LENSES
POTENTIALS
TIME DELAY