Imprint of Pressure on Characteristic Dark Matter Profiles: The Case of ESO0140040

Kuantay Boshkayev,Talgar Konysbayev,Marco Muccino,Ergali Kurmanov,Orlando Luongo

doi:10.3390/galaxies8040074

Abstract

We investigate the dark matter distribution in the spiral galaxy ESO0140040, employing the most widely used density profiles: the pseudo-isothermal, exponential sphere, Burkert, Navarro-Frenk-White, Moore and Einasto profiles. We infer the model parameters and estimate the total dark matter content from the rotation curve data. For simplicity, we assume that dark matter distribution is spherically symmetric without accounting for the complex structure of the galaxy. Our predictions are compared with previous results and the fitted parameters are statistically confronted for each profile. We thus show that although one does not include the galaxy structure it is possible to account for the same dynamics assuming that dark matter provides a non-zero pressure in the Newtonian approximation. In this respect, we solve the hydrostatic equilibrium equation and construct the dark matter pressure as a function for each profile. Consequently, we discuss the dark matter equation of state and calculate the speed of sound in dark matter. Furthermore, we interpret our results in view of our approach and we discuss the role of the refractive index as an observational signature to discriminate between our approach and the standard one.

Highlights

Understanding the nature and properties of dark matter (DM) is a challenging conundrum of our current Universe
The rotation curves (RCs) of such galaxies have amplitude that remains constant with increasing distance, even beyond the stellar disc, which is not expected in Newtonian gravity (NG) [8,9]
Newtonian gravity only and we investigate dark matter’s distributions using well-consolidated density profiles, among them: pseudo-isothermal (ISO), Burkert, Navarro-Frenk-White (NFW), Moore, Einasto and exponential sphere ones

Summary

Introduction

Understanding the nature and properties of dark matter (DM) is a challenging conundrum of our current Universe. Recent observations certify that DM amounts for about 26.8% of the total energy budget of the Universe [1], while from theoretical point of view it has been proposed that DM is made of some experimentally as yet undiscovered particles [2,3] coming. The number of approaches related to the DM problem is steadily growing, reflecting a noticeable interest in comprehending its nature [4,5,6], which constitutes the 85% of all the matter i.e., DM+baryons, and state function of baryons in the Universe. The RCs of such galaxies have amplitude that remains constant with increasing distance, even beyond the stellar disc, which is not expected in Newtonian gravity (NG) [8,9]

Objectives

Methods

Results