FIREbox: Simulating galaxies at high dynamic range in a cosmological volume

Abstract

We introduce a suite of cosmological volume simulations to study the evolution of galaxies at high numerical resolution as part of the Feedback in Realistic Environments project. FIREbox, the principal simulation of the present suite, provides a representative sample of galaxies (∼ 1000 galaxies with 𝑀 star > 10 8 𝑀 at 𝑧 = 0) at a resolution (Δ𝑥 ∼ 20 pc, 𝑚 b ∼ 6 × 10 4 𝑀 ) comparable to state-of-the-art galaxy zoom-in simulations. Furthermore, FIREbox captures the multiphase nature of the interstellar medium in a fully cosmological setting (𝐿 = 22.1 Mpc) thanks to its exceptionally high dynamic range ( 10 6 ) and the inclusion of multi-channel stellar feedback. Here, we focus on validating the predictions of FIREbox by comparing to observational data. We find that, at a given stellar mass (for 𝑀 star < 10 10.5−11 𝑀 ), simulated galaxies have star formation rates, atomic and molecular gas masses, gas phase and stellar metallicities in broad agreement with observations. In addition, FIREbox shows that these galaxy scaling relations extend to the low mass regime (𝑀 star ∼ 10 7 𝑀 ) and follow a (broken) power-law relationship. Also reproduced are the evolution of the cosmic H I density and the H I column density distribution at 𝑧 ∼ 0 − 5. At low 𝑧, FIREbox predicts a peak in the stellar-mass-halo-mass relation, but also a higher abundance of massive galaxies and a higher cosmic star formation rate density than observed, showing that stellar feedback alone is insufficient to reproduce the properties of massive galaxies at late times. Given its high resolution and sample size, FIREbox offers a baseline prediction of galaxy formation theory in a ΛCDM Universe while also highlighting modeling challenges to be addressed in next generation galaxy simulations.

Disruption of Dark Matter Minihaloes in the Milky Way environment: Implications for Axion Miniclusters and Early Matter Domination

“…A suite of N-body simulations is performed for minihaloes initialized with the NFW profile by varying minihalo concentrations, masses and impact parameters of the encountering stars. The simulations adopt the code G 4 (Hopkins 2015), which has been widely used in cosmological N-body or hydrodynamical simulations (e.g., Hopkins et al 2014Hopkins et al , 2018aFeldmann et al 2022). The goal of these simulations is to test and calibrate analytic predictions of the minihalo mass fraction disrupted in stellar encounters.…”

Realistic H i scale heights of Milky Way-mass galaxies in the FIREbox cosmological volume

“…In this letter we study galaxies drawn from the (22.1 Mpc) 3 F box cosmological volume simulation (Feldmann et al 2022) that is part of the Feedback In Realistic Environments (F ) project 1 .The simulation was run with the meshless-finite-mass code G 2 (Hopkins 2015) and the F -2 (Hopkins et al 2018) sub-grid physics. Specifically, these simulations use the Hopkins et al (2014) cooling and heating rates valid for temperatures ranging from 10−10 9 K, including heating and photoionisation from a Faucher-Giguère et al ( 2009) UV Background, naturally resulting in a multiphase interstellar medium (ISM) that includes a cold gas phase.…”

“…Encouragingly, thin cold gas discs have been found in several 𝐿 * galaxies simulated with the F -2 model (Sanderson et al 2020;Gurvich et al 2020;Trapp et al 2022), but no systematic exploration with a focus on the HI has been conducted yet. The F box cosmological volume (Feldmann et al 2022), with its high spatial resolution (∼20 pc), and multiphase ISM, that yields 20-30 𝐿 * galaxies, is ideally suited to systematically analyse the H discs of 𝐿 * galaxies. In this letter, we focus on their scale heights in particular, measuring them with the variety of different methods used in the literature.…”

Realistic HI scale heights of Milky Way-mass galaxies in the FIREbox cosmological volume

“…In this letter we study galaxies drawn from the (22.1 Mpc) 3 F box cosmological volume simulation (Feldmann et al 2022) that is part of the Feedback In Realistic Environments (F ) project 1 .The simulation was run with the meshless-finite-mass code G 2 (Hopkins 2015) and the F -2 (Hopkins et al 2018) sub-grid physics. Specifically, these simulations use the Hopkins et al (2014) cooling and heating rates valid for temperatures ranging from 10−10 9 K, including heating and photoionisation from a Faucher-Giguère et al ( 2009) UV Background, naturally resulting in a multiphase interstellar medium (ISM) that includes a cold gas phase.…”

“…Encouragingly, thin cold gas discs have been found in sev-eral 𝐿 * galaxies simulated with the F -2 model (Sanderson et al 2020;Gurvich et al 2020;Trapp et al 2022), but no systematic exploration with a focus on the HI has been conducted yet. The F box cosmological volume (Feldmann et al 2022), with its high spatial resolution (∼20 pc), and multiphase ISM, that yields 20-30 𝐿 * galaxies,is ideally suited to systematically analyse the H discs of 𝐿 * galaxies. In this letter, we focus on their scale heights in particular, measuring them with the variety of different methods used in the literature.…”