Strong lensing as a test for conformal Weyl gravity

Conformal Weyl gravity (CWG) predicts galactic rotation curves without invoking dark matter. This makes CWG an interesting candidate theory as an alternative to general relativity (GR). This removal of the necessity for dark matter arises because the exact exterior solution in CWG for a static, sphe...

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Bibliographic Details
Published inMonthly notices of the Royal Astronomical Society Vol. 441; no. 2; pp. 1291 - 1296
Main Authors Cutajar, Deandra, Zarb Adami, Kristian
Format Journal Article
LanguageEnglish
Published London Oxford University Press 21.06.2014
Subjects
Cosmology
Dark matter
Gravity
Orbits
Star & galaxy formation
gravitational lensing: strong
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Summary:Conformal Weyl gravity (CWG) predicts galactic rotation curves without invoking dark matter. This makes CWG an interesting candidate theory as an alternative to general relativity (GR). This removal of the necessity for dark matter arises because the exact exterior solution in CWG for a static, spherically symmetric source provides a linear potential γr, which can explain the observed galactic rotation curves with a value for γ of ∼+10−26 m−1. Previous work has also shown that CWG can explain lensing observations, but with γ ∼ −10−26 m−1, in order to ensure converging rays of light rather than diverging ones. Even though different expressions for the angle of deflection have been derived in CWG in order to remove this inconsistency, this article shows that the γ required to fit the lensing data is several orders of magnitude higher than that required to fit galactic rotation curves.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stu617