Astronomy Colloquium for 2019-02-21


Series: Astronomy Colloquium
Date: Thursday 21-Feb-2019
Time: 16:05-17:00 (4:05-5:00 pm)
Location: ATL 2234 ** NOTE NEW DATE AND LOCATION DUE TO WEATHER CLOSING **
Speaker: Dr. Evan Schneider (Princeton University)
Title: The origin of multiphase galaxy outflows

Star-forming galaxies are often observed to host galactic winds - gas that is flowing out of the galaxy in phases ranging from cold molecular clouds to hot X-ray emitting plasma. While these multiphase outflows are routinely observed, theoretically constraining their origin and evolution has proven difficult. Explaining the prevalence and velocities of the cool ionized phase (T~10^4 K) in particular poses a challenge. In this talk, I will discuss a potential dual origin for this cool gas. Through a series of extremely high-resolution simulations run with the GPU-based Cholla code, I will show that in high star formation surface density systems, dense disk gas can be pushed out by the collective effect of clustered supernovae, explaining the low-velocity material. Simultaneously, shredding and mixing of these clouds increases the density of the hot phase of the wind, leading to large-scale radiative losses that produce high velocity cool gas. In addition to explaining the nature of outflows themselves, these multiphase winds could potentially be a source of the cool photo-ionized gas that is found in abundance in galaxy halos.


Colloquia are usually preceded by espresso and ice cream at 1:45 pm outside room PSC 1150 and are followed by an informal reception at 5:15 pm in that room. Anyone interested in talking with the speaker, or being added to the colloquium announcement email list, should contact the colloquium organizer. Lunch will normally be reserved for the speaker to talk to graduate students. Anyone asking a question during a talk is asked to raise their hand and be acknowledged before speaking.

Colloquium Organizer: Prof. Richard Mushotzy

SPECIAL ACCOMMODATIONS:

Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.

DIRECTIONS, PARKING, AND OTHER INFORMATION FOR VISITORS

Directions and information about parking can be found here.

This page was automatically generated on: 26-Apr-2019.