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Astronomy Colloquium Series Presents

Dr. Elisabeth Mills, Research Assistant Professor, Brandeis University
Thursday, October 17, 2019
3:30-4:30 PM
411 West Hall Map
The Journey or the Destination: Isolating the Origin of the Physics Driving Gas Conditions in Galaxy Nuclei

Centers of galaxies are some of the most extreme objects in our universe: hosting starbursts and active supermassive black holes that can launch jets and winds far outside the compact galaxy nucleus. While there are relics of an active past in the center of our own Milky Way, at present it does not exhibit any of this activity. However, the central 300 parsecs of our Galaxy does contain a sizable reservoir of molecular gas that is the fuel for future star formation and black hole accretion. Constraining the physical conditions of this gas is critical for understanding how this reservoir will evolve to influence future activity in the Milky Way’s nucleus. Determining the origin of these conditions is also key to determining whether the same physics that govern gas conditions in this region can help us interpret more distant and active galaxy nuclei. I will present the results of my recent work following the changes in physical properties of this gas as it approaches the black hole; increasing in temperature, density, and turbulence, while largely resisting the onset of star formation. This work provides evidence that the extreme gas conditions in this region are driven largely by infall processes: the journey it takes to reach the central parsecs, rather than the energetic phenomena (supernovae, cosmic rays, massive star winds, UV radiation, and occasional X-ray flaring) encountered at its destination. However, as our Galactic center is relatively inactive, the next challenge is determining the extent to which the physics at work here are representative of more active systems. I will conclude by discussing work I am doing to double my sample size of galaxy nuclei by observing the ionized and molecular gas in the center of NGC 253, a nearby galaxy with an order of magnitude more star formation. Comparison of these two galaxy centers will isolate the gas conditions that both govern and are influenced by a nuclear starburst, and allow the definition of local templates for understanding the gas physics in these regions

Please note: Should you require any accommodations to ensure equal access and opportunity related to this event please contact Stacy Tiburzi at 734-764-3440 or

Tea will be served beforehand from 3:00-3:30pm in Serpens.
Building: West Hall
Event Type: Lecture / Discussion
Tags: astronomy, Climate and Space Sciences and Engineering, lecture, physics
Source: Happening @ Michigan from Department of Astronomy, Department of Physics, Michigan Institute for Research in Astrophysics