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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Observation shows that nebular emission, molecular gas, and young stars ingiant galaxies are associated with rising X-ray bubbles inflated by radio jetslaunched from nuclear black holes. We propose a model where molecular cloudscondense from low entropy gas caught in the updraft of rising X-ray bubbles.The low entropy gas becomes thermally unstable when it is lifted to an altitudewhere its cooling time is shorter than the time required to fall to itsequilibrium location in the galaxy i.e., t_c/t_I < 1. The infall speed of acloud is bounded by the lesser of its free-fall and terminal speeds, so thatthe infall time here can exceed the the free-fall time by a significant factor.This mechanism is motivated by ALMA observations revealing molecular cloudslying in the wakes of rising X-ray bubbles with velocities well below theirfree-fall speeds. Our mechanism would provide cold gas needed to fuel afeedback loop while stabilizing the atmosphere on larger scales. The observedcooling time threshold of ~ 5x 10^8 yr --- the clear-cut signature of thermalinstability and the onset of nebular emission and star formation--- may resultfrom the limited ability of radio bubbles to lift low entropy gas to altitudeswhere thermal instabilities can ensue. Outflowing molecular clouds are unlikelyto escape, but instead return to the central galaxy in a circulating flow. Wecontrast our mechanism to precipitation models where the minimum value oft_c/t_ff < 10 triggers thermal instability, which we find to be inconsistentwith observation.

A Mechanism for Stimulating AGN Feedback by Lifting Gas in Massive Galaxies