Journal
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 468, Issue 4, Pages 4801-4814Publisher
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stx822
Keywords
galaxies: evolution; galaxies: formation; galaxies: fundamental parameters; galaxies: starburst; X-rays: galaxies
Categories
Funding
- NASA [NNX10AD01G]
- NSF [AST-1616171, 1516967]
- NASA ATP Grant [12-ATP12-0183]
- Simons Foundation
- David and Lucile Packard Foundation
- Thomas Alison Schneider Chair in Physics
- NSERC of Canada
- Canada Research Chair programme
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [1516967, 1616171] Funding Source: National Science Foundation
Ask authors/readers for more resources
Efficient thermalization of overlapping supernovae within star-forming galaxies may produce a supernova-heated fluid that drives galactic winds. For fiducial assumptions about the timescale for cloud shredding from high-resolution simulations (which neglect magnetic fields), we show that cool clouds with temperature from T-c similar to 10(2)-10(4) K seen in emission and absorption in galactic winds cannot be accelerated to observed velocities by the ram pressure of a hot wind. Taking into account both the radial structure of the hot flow and gravity, we show that this conclusion holds over a wide range of galaxy, cloud and hot wind properties. This finding calls into question the prevailing picture whereby the cool atomic gas seen in galactic winds is entrained and accelerated by the hot flow. Given these difficulties with ram pressure acceleration, we discuss alternative models for the origin of high-velocity cool gas outflows. Another possibility is that magnetic fields in cool clouds are sufficiently important that they prolong the cloud's life. For T-c = 10(3) K and 10(4) K clouds, we show that if conductive evaporation can be neglected, the cloud shredding time-scale must be similar to 15 and 5 times longer, respectively, than the values from hydrodynamical simulations in order for cool cloud velocities to reach those seen in observations.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available