[Paper Review] A Brief Review of Galactic Winds

Timothy M. Heckman, Todd A. Thompson|arXiv (Cornell University)|Jan 31, 2017

Galaxies: Formation, Evolution, Phenomena40 references5 citations

TL;DR

This paper reviews the physical mechanisms driving galactic winds in star-forming galaxies, emphasizing momentum and energy input from massive stars and supernovae. Using M82 as a prototype, it demonstrates the multiphase nature of winds and shows how wind properties correlate systematically with host galaxy characteristics, highlighting their critical role in enriching the inter-galactic medium and regulating galaxy evolution.

ABSTRACT

Galactic winds from star-forming galaxies play at key role in the evolution of galaxies and the inter-galactic medium. They transport metals out of galaxies, chemically-enriching the inter-galactic medium and modifying the chemical evolution of galaxies. They affect the surrounding inter-stellar and circum-galactic media, thereby influencing the growth of galaxies through gas accretion and star-formation. In this contribution we first summarize the physical mechanisms by which the momentum and energy output from a population of massive stars and associated supernovae can drive galactic winds. We use the proto-typical example of M82 to illustrate the multiphase nature of galactic winds. We then describe how the basic properties of galactic winds are derived from the data, and summarize how the properties of galactic winds vary systematically with the properties of the galaxies that launch them. We conclude with a brief discussion of the broad implications of galactic winds.

Motivation & Objective

• To understand the physical mechanisms by which massive stars and supernovae drive galactic winds.
• To examine the multiphase structure of galactic winds using M82 as a canonical example.
• To derive and analyze the fundamental properties of galactic winds from observational data.
• To investigate how wind properties correlate with the characteristics of their host galaxies.
• To assess the broader implications of galactic winds for galaxy and inter-galactic medium evolution.

Proposed method

• Analysis of momentum and energy feedback from stellar populations and supernovae as the primary driver of galactic winds.
• Use of M82 as a prototypical case study to illustrate the multi-phase (hot, warm, cold) structure of galactic winds.
• Extraction of wind properties (e.g., mass outflow rate, velocity, metallicity) from multi-wavelength observational data.
• Systematic comparison of wind properties across different galaxies to identify correlations with host galaxy parameters.
• Application of theoretical models to interpret observational wind signatures and constrain feedback efficiency.

Experimental results

Research questions

• RQ1 What physical mechanisms transfer momentum and energy from massive stars and supernovae to drive galactic winds?
• RQ2 How does the multiphase nature of galactic winds manifest in a prototypical starburst galaxy like M82?
• RQ3 What are the key observational diagnostics used to derive the fundamental properties of galactic winds?
• RQ4 How do wind properties such as mass outflow rate and velocity scale with the properties of the host galaxy?
• RQ5 What are the large-scale implications of galactic winds for chemical enrichment of the inter-galactic medium and galaxy evolution?

Key findings

• Galactic winds are driven primarily by the combined momentum and energy input from massive stars and supernovae in star-forming regions.
• The wind in M82 exhibits a multi-phase structure, including hot, ionized gas, warm ionized and neutral components, and cold, dense clumps.
• Wind mass outflow rates and velocities are systematically correlated with the star formation rate and stellar mass of the host galaxy.
• Galactic winds efficiently transport metals out of galaxies, chemically enriching the inter-galactic medium.
• The feedback from galactic winds regulates gas accretion and star formation, thereby influencing the long-term evolution of galaxies.