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Elliptical galaxies are systems where dark matter is usually less necessaryto explain observed dynamics than in the case of spiral galaxies, however thereare some instances where Newtonian gravity and the observable mass areinsufficient to explain their observed structure and kinematics. Such is thecase of NGC 4649, a massive elliptical galaxy in the Virgo cluster for whichrecent studies report a high fraction of dark matter, 0.78 at $4R_e$. Howeverthis galaxy has been studied within the MOND hypothesis, where a good agreementwith the observed values of velocity dispersion is found. Using a MONDiangravity force law, here we model this galaxy as a self-consistent gravitationalequilibrium dynamical system. This force law reproduces the MOND phenomenologyin the $a<a_{0}$ regime, and reduces to the Newtonian case when $a>a_{0}$.Within the MONDian $a<a_{0}$ scales, centrifugal equilibrium or dispersionvelocities become independent of radius, and show a direct proportionality tothe fourth root of the total baryonic mass, $V^{4}\propto(M G a_{0})$. We findthat the recent detailed observations of the surface brightness profile and thevelocity dispersion profile for this galaxy are consistent with thephenomenology expected in MONDian theories of modified gravity, without theneed of invoking the presence of any hypothetical dark matter.

The massive elliptical galaxy NGC 4649 from the perspective of extended gravity