Confronting MOND and TeVeS with strong gravitational lensing over galactic scales: an extended survey

Abstract

The validity of MOND and TeVeS models of modified gravity has been recently tested by using lensing techniques, with the conclusion that a non-trivial component in the form of dark matter is needed in order to match the observations. In this work those analyses are extended by comparing lensing to stellar masses for a sample of nine strong gravitational lenses that probe galactic scales. The sample is extracted from a recent work that presents the mass profile out to a few effective radii, therefore reaching into regions that are dominated by dark matter in the standard (general relativity) scenario. A range of interpolating functions are explored to test the validity of MOND/TeVeS in these systems. Out of the nine systems, there are five robust candidates with a significant excess (higher that 50%) of lensing mass with respect to stellar mass, irrespective of the stellar initial mass function. One of these lenses (Q0957) is located at the centre of a galactic cluster. This system might be accommodated in MOND/TeVeS via the addition of a hot component, like a 2 eV neutrino, that contribute over cluster scales. However, the other four robust candidates (LBQS1009, HE1104, B1600, HE2149) are located in field/group regions, so that a cold component (CDM) would be required even within the MOND/TeVeS framework. Our results therefore do not support recent claims that these alternative scenarios to CDM can survive astrophysical data.