Modification of Newtonian gravity: Implications for hot gas in clusters and galactic angular momentum

Abstract

In view of the negative results from various dark matter detection experiments, we had earlier proposed an alternate theoretical framework through modification of Newtonian gravity (MONG). Here, the Poison’s equation is modified by introducing an additional gravitational self-energy density term along with the usual dark energy density term. In this work, we extend this model to account for the presence of low-density gas at high temperatures (1⁢08⁢𝐾) in the intra cluster medium (ICM) by estimating the velocities to which particles will be subjected by the modified gravitational force. Considering that the ICM is under the influence of the cluster’s gravity, particle velocities of the ions in the ICM must be balanced by the cluster’s gravitational force. The particle velocities obtained for various clusters from their temperature profiles match the velocity produced by the MONG gravitational force. Thus, the increase in the gravitational potential at the outskirts of galaxies balances the thermal pressure of the ICM, maintaining hydrostatic equilibrium without invoking DM. The effect of MONG on the angular momentum of galaxies is also studied by obtaining a scaling relation between the angular momentum and the mass of a galaxy. MONG predicts a higher dependence on mass in comparison to the Λ CDM model. This increased dependence of angular momentum on mass compensates for the halo contribution to the angular momentum. The angular momentum from MONG for galaxies from the spritzer photometry and accurate rotation curves (SPARC) database is compared to the halo angular momentum by a chi-square fit technique. The correlation coefficient is found to be unity, showing a replicable result.