Dwarf galaxies at the steep and faint end of the Tully Fisher relation

TL;DR

This paper proposes that the thermal environment of dwarf galaxies influences their rotation curves and Tully-Fisher relation steepness, with the Debye Gravitational Theory explaining these properties through temperature-dependent isothermal curves.

Contribution

It introduces the application of Debye Gravitational Theory to dwarf galaxies, linking their properties to thermal bath temperatures, and explains the steep faint end of the Tully-Fisher relation.

Findings

Dwarf galaxy properties depend on thermal bath temperatures from 2.73 K to 3.80 K.

DGT predictions align well with observational data for dwarf galaxies.

The steep TFR at the faint end is explained by thermal effects on dwarf galaxies.

Abstract

Nearby isolated galaxies ($z\sim 0$), are considered immerse within a thermal bath at 2.73 K. However the dwarf galaxies orbiting these galaxies are also subject to additional radiation from their hosts, so they are within a thermal bath slightly warmer. We claim that this thermal effect can explain several properties of the dwarf galaxies, such as their rotation curves, their radial acceleration relations (RAR) and why the velocity-mass dependence at the faint end of the Tully Fisher Relation (TFR) is steeper for these galaxies. In the Debye Gravitational Theory (DGT), the galaxies properties, such as the rotation curves, the RARs, and the TFRs are isothermal curves; they depend explicitly only of temperature, of the thermal bath in which are immersed. We show that the steep and faint end of the TFR is composed of a mixture of dwarf galaxies immersed in thermal baths with temperatures from 2.73 K to 3.80 K. A comparison among DGT's predictions for the dwarf galaxies relations with data obtained from the literature show a satisfactory agreement between them.