Dark matter distribution in galaxy U11454

Abstract

In this paper the dark matter distribution in the spiral galaxy U11454 is explored using only the well -known cored density profiles in the literature such as the pseudo-isothermal, Burkert, Einasto, exponential sphere, Beta and Brownstein profiles. It is assumed that the distribution of dark matter in the considered galaxy is spherically symmetric without taking into account its complex structural components. Instead, it is assumed that dark matter possesses non-vanishing pressure. The rotation curve data of the galaxy is fitted for each profile. The model free parameters are inferred, the total dark matter mass for each profile is calculated and our results are confronted and co ntrasted with the previous outcomes. Using 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. In addition, the speed of sound is estimated in the dark matter di stribution 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 produced by the presence of dark matter and astrophysical implications of the obtained results are discussed.