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Past Events
Large-Scale Outflows from Starforming Galaxies and Cosmic-Ray Heating in Protogalactic Environments
| Speaker: | Prof. Kinwah Wu |
| Affiliation: | Mullard Space Science Laboratory, University College London, UK |
| Date: | January 23, 2018 (Tuesday) |
| Time: | 4:30 p.m. |
| Venue: | Room 522, 5/F, Chong Yuet Ming Physics Building, HKU |
Abstract
Galaxies with strong star-forming activity are found to have large-scale outflows. These outflows are multi-phase, multi-component media, consisting of a mixture of ionised and neutral gases, in the form of bubbles and clamps respectively. The flows are often laden with particles, such as dusts, and are permeated by tangled magnetic fields. These flows are complicated. Protogalaxies with strong formation are expected to show large-scale outflows. These galaxies undergo strong star-forming processes, which lead to frequent supernova events. The supernova explosions not only supply the energy to drive the galactic outflows but also generate shocks and accelerate charged particles to ultra-relativistic energies, i.e. UHE cosmic rays (CRs). The UHE CRs will interact with their host galaxies, causing heating of the interstellar medium. The UHE CRs may be advected out from the galaxies, delivering chemically enriched material and energy to the environments. In this talk I will discuss the properties of multi-phase, multi-component protogalactic outflows and CR heating in the protogalactic environment in the presence of large-scale outflows.
I will show the new results of our recent calculation and discuss their astrophysical implications.
Anyone interested is welcome to attend.