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

The validity of modified Newtonian dynamics (MOND) and tensor vector scalar (TeVeS) models of modified gravity has been recently tested by using lensing techniques, with the conclusion that a nontrivial 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 which probe galactic scales. The sample is extracted from a recent work which presents the mass profile out to a few effective radii, therefore reaching into regions which 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 than 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 center of a galactic cluster. This system might be accommodated in MOND/TeVeS via the addition of a hot component, like a 2 eV neutrino, which contributes over cluster scales. However, the other four robust candidates (LBQS1009, HE1104, B1600, HE2149) are located in field/group regions, so that a cold component (cold dark matter) would be required even within the MOND/TeVeS framework. Our results, therefore, do not support recent claims that these alternative scenarios to cold dark matter can survive astrophysical data.

Figure 1

Plots of the aperture lensing mass of the systems versus the percentage discrepancy after comparison with the aperture stellar masses. The percentage difference between the stellar masses and the lensing masses are an indication of the dark matter required by the system. $M_{\mathrm{TOT}}$ is the lensing mass estimates within the aperture radius, and $M_{\mathrm{STAR}}$ is the stellar mass estimate from Ref. 14. Plot for Chabrier stellar masses. GR represents the lensing mass when calculated using standard general relativity, and MOND when using the modified gravity.

Figure 2

Plots of the aperture lensing mass of the systems versus the percentage discrepancy after comparison with the aperture stellar masses. The percentage difference between the stellar masses and the lensing masses are an indication of the dark matter required by the system. $M_{\mathrm{TOT}}$ is the lensing mass estimates within the aperture radius, and $M_{\mathrm{STAR}}$ is the stellar mass estimate from Ref. 14. Plot for Salpeter stellar masses. GR represents the lensing mass when calculated using standard general relativity, and MOND when using the modified gravity.