The Effects of Cosmic Ray Protons on Galactic Nonthermal Filaments
POSTER
Abstract
The Galactic Center (GC) contains a collection of synchrotron-emitting filaments that host cosmic rays (CRs). These nonthermal filaments (NTFs) are tens of parsecs long and are predominantly controlled by CR transport, but their origins are unclear. We aim to distinguish two injection theories: they are fueled either by jets from pulsar wind nebulae, and are lepton-dominated; or by accelerated particles from interstellar shocks, and are proton-dominated. We test these theories using the magnetohydrodynamic code (MHD) Athena++ to simulate CR propagation with different CR species. We vary parameters such as magnetic field strength, plasma density, and the CR diffusion coefficient to determine how the GC's uncertain conditions can affect CRs' propagation, heating, plasma flow, and the observed synchrotron emission. By analyzing these cases, we can constrain source models and improve our understanding of the physics underpinning NTFs. We also briefly consider a third origin theory: that the filaments arise from transient compressions manifesting from interstellar turbulence.
*This project was funded by NASA award #09-0054, NSF award AST-2007323, the Simons Collaboration for Extreme Electrodynamics of Compact Sources, and UW-Madison's Community of Graduate Research Scholars fellowship.
Presenters
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Mohan Richter-Addo
- University of Wisconsin - Madison