Abstract Details

Name: Alankar Dutta
Affiliation: Indian Institute of Science
Conference ID: ASI2020_291
Title : Fate of cold clouds in hot galactic outflows
Authors and Co-Authors : Alankar Dutta and Prateek Sharma
Abstract Type : Poster
Abstract Category : Extragalactic Astronomy
Abstract : Absorption and emission lines studies of the Circumgalactic medium indicate the presence of cold gas with high velocity dispersion (~few 100s of km s^-1). One possibility is that the cold gas is accelerated by the hot wind generated from energetic outflows driven by supernovae or AGN. A long-standing problem with such models is that the cloud is mixed in with the hot outflow before being significantly uplifted (Klein et al 1994). Gronke and Oh (2018 and 2019) recently showed that radiative cooling can overcome the above problem. The cold gas mass can increase as more and more gas from the hot phase is entrained and cooled in the wake of the cloud. This may explain the high velocity multiphase gas observed in energetic outflows. We investigate the dynamics of the long trails of entrained cold gas formed in the steady state of Gronke-Oh simulations by modelling them as a pressure-driven cooling flow. We also implement this model in a more realistic spherically expanding Chevalier-Clegg (CC85) type outflow. We express the Gronke-Oh criterion in terms of the energy and mass injection parameters of the CC85 wind. We compare our results with the observations of galactic outflows.