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Orbital Torus Imaging on FIRE

Presentation #405.02 in the session Analysis of equilibrium collisionless systems: power and peril.

Published onApr 25, 2022
Orbital Torus Imaging on FIRE

In this presentation, I will discuss Orbital Torus Imaging (OTI), a new dynamical inference method to measure the Milky Way’s potential. OTI leverages gradients in stellar astrophysical quantities (like age and chemical abundances) as a function of dynamical quantities (like orbital actions or energy) — these quantities are newly available from large surveys like SDSS and Gaia. Initial analysis has yielded promising results; however, it is unknown how sensitive this technique is to the effects of disequilibria. It is therefore important to test this method on simulations wherein the potential is realistic and known. I will discuss my implementation of OTI for a 1-dimensional system with an isothermal distribution function embedded in a simple harmonic oscillator potential and successful recovery of the true potential parameter. I will also discuss testing OTI on several Feedback in Realistic Environments (FIRE) hydrodynamic simulations. Particularly, I will discuss my investigation of the impact of a merger event on the accuracy of this method to recover the true potential. Additionally, I will investigate how local overdensities from the star forming gas and feedback processes from spiral arms affect the results from this method. The FIRE cosmological simulations are an ideal testbed for OTI, as these simulated galaxies span a range of formation histories, allowing me to explore the limits on how well this method measures the dark matter potential. This research will inform our understanding of the bias of this novel method and allow us to improve the modeling to handle effects we find in simulations.

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