On the theory of mass loss in dwarf galaxies: I - basic equations and the case of wave/thermal driven winds

TL;DR

This paper develops a semi-analytical model of galactic winds in dwarf galaxies, examining how thermal, turbulent, and dark matter distribution factors influence mass loss rates and wind properties.

Contribution

It introduces a comprehensive semi-analytical framework that incorporates wave heating, cooling processes, and dark matter profiles to study dwarf galaxy winds.

Findings

Dwarf galaxies can sustain quasi-stationary winds with significant mass loss rates.

Wind mass loss is higher with cusped dark matter profiles like NFW.

Heating to temperatures above 10^4-10^5 K promotes wind development.

Abstract

In this work we present a semi-analytical model of galactic wind for dwarf galaxies where thermal and turbulent/momemtum driving mechanisms are studied. The model takes into account wave and internal adiabatic heating mechanisms, as well as radiative and adiabatic cooling. The importance of external sources of energy is discussed. We also studied the role of the spatial distribution of dark matter in the acceleration of the wind and on the mass loss rates. The basic model parameters that regulate the wind mass loss rate and terminal velocity are the gravitational potential profile, the equilibrium temperature of the gas and the amplitude of the turbulent motions of the gas. We found that dwarf galaxies are likely to present quasi-stationary winds with mass loss rates larger than $10^{-3}$M$_{\odot}$yr$^{-1}$ even in the absence of turbulent motions (which is possibly related to the SNe feedback), if the interstellar gas is heated to $T > 10^4 - 10^5$K. We also found that the wind mass loss rate is enhanced for cusped dark matter distributions, such as the NFW-profile, due to the increased pressure gradients at the center of the galaxy. The solutions presented here may serve as benchmarks for numerical simulations, and as inputs for single zone chemical evolution models of dwarf galaxies.