Comparison of HMG and Flat Rotation Velocities Inferred from Galaxy–Galaxy Weak Lensing

Abstract Despite the success of dark matter models, unresolved issues require exploring alternatives such as modified gravity theories. In this context, we examine the compatibility of the hyperconical modified gravity (HMG) with galaxy rotation curves inferred from weak-lensing data. The research addresses the existing limitations of modified Newtonian dynamics (MOND), which often struggle with universal applicability across different galactic scales. By assuming local validity of general relativity and analyzing recent data on circular velocities from galaxy–galaxy weak lensing, our findings interpret the flat rotation curves as an effect of fictitious acceleration inherited from the cosmic expansion, without invoking dark matter. The results indicate that HMG successfully reproduces flat velocity curves on scales of 1 Mpc slightly better than MOND. Therefore, these observations support HMG as a viable gravitational model, highlighting its potential to account for dynamics on galaxies and other scales. Further research with extensive data sets is required to confirm these preliminary insights.