English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present a new theoretical framework for using entropy to understand howoutflows driven by supernovae are launched from disc galaxies: via continuous,buoyant acceleration through the circumgalactic medium (CGM). When young starclusters detonate supernovae in the interstellar medium (ISM) of a galaxy, theygenerate hot, diffuse bubbles that push on the surrounding ISM and evaporatethat ISM into their interiors. As these bubbles reach the scale height of theISM, they break out of the disc, rising into the CGM. Once these bubbles breakout, if they have sufficiently high entropy, they will feel an upwardacceleration, owing to a local buoyant force. This upward force will acceleratethese bubbles, driving them to high galactocentric radii, keeping them in theCGM for $>\Gyr$, even if their initial velocity is much lower than the localescape velocity. We derive an equation of motion for these entropy-driven windsthat connects the ISM properties, halo mass, and CGM profile of galaxies to theultimate evolution of feedback-driven winds. We explore the parameter space ofthese equations, and show how this novel framework can explain bothself-consistent simulations of star formation and galactic outflows as well asthe new wealth of observations of CGM kinematics. We show that theseentropy-driven winds can produce long wind recycling times, while stillcarrying a significant amount of mass. Comparisons to simulations andobservations show entropy-driven winds convincingly explain the kinematics ofgalactic outflows.

Entropy Driven Winds: Outflows and Fountains Lifted Gently by Buoyancy