Surface Density Discrepancy of Elliptical Galaxies
Yong Tian1*, Chung-Ming Ko1,2
1Institute of Astronomy, National Central University, Taoyuan City, Taiwan
2Department of Physics and Center of Complex System, National Central University, Taoyuan City, Taiwan
* presenting author:Yong Tian, email:yongtian@astro.ncu.edu.tw
The discrepancy between dynamical and stellar surface density of 135 disk galaxies (S0 to dIrr) was reported by Felli et. al. (2016) recently. The criterion of surface density discrepancy is related to the acceleration constant a₀ and can be explained by modified Newtonian dynamics (MOND). From a catalog of early-type galaxies by Dabringhausen & Fellhauer (2016), around 500 elliptical galaxies can be studied in both dynamical and stellar mass surface density. We find similar result as in disk galaxies, i.e., the discrepancy between the two mass density increases as the surface density becomes small. This can be identified with the acceleration constant a₀ in MOND as well. Moreover, the mass discrepancy increases as Newtonian acceleration decreases. It is consistent with the prediction of MOND.


Keywords: Elliptical Galaxy, Modified Gravity, Dark Matter