Physical properties of dark matter in galaxy U11454

Abstract

In this paper physical characteristics of dark matter distribution in the spiral galaxy U11454 is explored using only well-known cored density profiles in the literature such as the pseudo-isothermal, Burkert, Einasto, exponential sphere, Beta and Brownstein profiles. It is presumed that the distribution of dark matter in the considered galaxy is spherically symmetric without taking into account its complex structural components. It is assumed that dark matter possesses non-vanishing pressure which allows theoretically analyzing the state parameter. The model free parameters of each profile are inferred from the rotation curve data of the galaxy by means of non-linear model fit procedure. Using the Bayesian Information Criterion the best fit profile among the considered ones is selected. Furthermore, the hydrostatic equilibrium equation is solved and the pressure profiles for each above mentioned density profile are constructed in the weak gravitational field regime. Combining the pressure and corresponding density profiles one gains equations of state for the dark matter in the galaxy U11454. The mass and gravitational potential are evaluated and constructed as a function of the radial distance for each profile. The total dark matter mass is assessed and our results are confronted and contrasted with the previous outcomes. In addition, the speed of sound is estimated in the dark matter distribution and it is shown that its behavior is quite unusual especially for the Brownstein profile. Finally, the refracting index is calculated in order to assess gravitational lensing effects produce