Testing Bekenstein's relativistic Modified Newtonian Dynamics with lensing data
Abstract
We propose to use multipleimaged gravitational lenses to set limits on gravity theories without dark matter, specifically tensorvectorscalar (TeVeS) theory, a theory which is consistent with fundamental relativistic principles and the phenomenology of Modified Newtonian Dynamics (MOND) theory. After setting the framework for lensing and cosmology, we analytically derive the deflection angle for the point lens and the Hernquist galaxy profile, and study their patterns in convergence, shear and amplification. Applying our analytical lensing models, we fit galaxyquasar lenses in the CfAArizona Space Telescope Lens Survey (CASTLES) sample. We do this with three methods, fitting the observed Einstein ring sizes, the image positions, or the flux ratios. In all the cases, we consistently find that stars in galaxies in MOND/TeVeS provide adequate lensing. Bekenstein's toy μ function provides more efficient lensing than the standard MOND μ function. But for a handful of lenses, a good fit would require a lens mass orders of magnitude larger/smaller than the stellar mass derived from luminosity unless the modification function μ and modification scale a_{0} for the universal gravity were allowed to be very different from what spiral galaxy rotation curves normally imply. We discuss the limitation of present data and summarize constraints on the MOND μ function. We also show that the simplest TeVeS `minimalmatter' cosmology, a baryonic universe with a cosmological constant, can fit the distanceredshift relation from the supernova data, but underpredicts the sound horizon size at the last scattering. We conclude that lensing is a promising approach to differentiate laws of gravity.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 May 2006
 DOI:
 10.1111/j.13652966.2006.10023.x
 arXiv:
 arXiv:astroph/0509590
 Bibcode:
 2006MNRAS.368..171Z
 Keywords:

 gravitational lensing;
 cosmology: theory;
 Astrophysics
 EPrint:
 reduced to 17p, 16 figs, discussed cosmology and constraints on mufunction, MNRAS accepted