TensorFlow Hydrodynamics Analysis for Ly-$\hat{I}\pm$ Simulations

Abstract

We introduce the Python program THALAS (TensorFlow Hydrodynamics Analysis for Lyman-Alpha Simulations), which maps baryon fields (baryon density, temperature, and velocity) to Ly$\hat{I}\pm$ optical depth fields in both real space and redshift space. Unlike previous Ly$\hat{I}\pm$ codes, THALAS is fully differentiable, enabling a wide variety of potential applications for general analysis of hydrodynamical simulations and cosmological inference. To demonstrate THALAS's capabilities, we apply it to the Ly$\hat{I}\pm$ forest inversion problem: given a Ly$\hat{I}\pm$ optical depth field, we reconstruct the corresponding real-space dark matter density field. Such applications are relevant to both cosmological and three-dimensional tomographic analyses of Lyman Alpha forest data.

19 pages, 6 figures