Physics at Virginia

"Mapping the Local Bubble's Magnetic Field in 3D"

Theo O'Neill , UVA
[Host: Stefan Baessler]

Our solar system is embedded in the Local Bubble, an expanding, 1,000-light-year-wide cavity in the interstellar medium (ISM).  The Bubble was created ~14 million years ago by a chain of supernova explosions that drove out most of the diffuse dust and gas in the nearby ISM.  Recent work mapping the 3D shape and dynamics of the Local Bubble has revealed that nearly all recent star formation within
200 pc of the Sun was triggered by the Bubble's rapid expansion.  The exact mechanics of this expansion, and the role that magnetic fields in the ISM have played in regulating its evolution, is not yet clear.  By combining detailed models of the Bubble’s geometry (derived from 3D dust
mapping) with Planck dust polarization observations and the assumption that magnetic field vectors are tangent to the Bubble’s surface, we are able to infer the Bubble’s 3D magnetic field orientation.  This map is the first to fully chart magnetic fields over an observed superbubble in 3D.  We analyze the relationship between the Local Bubble’s magnetic field and background starlight polarimetry observations, and discuss how magnetic fields may have affected the dynamics of the Local Bubble and progression of nearby star formation.

Friday, February 24, 2023
3:30 PM
Clark Hall, Room 108
Note special room.

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