Three-phase Interstellar medium in Galaxies Resolving Evolution with Star formation and Supernova feedback (TIGRESS): Algorithms, Fiducial model, and Convergence

TL;DR

TIGRESS is a comprehensive simulation framework for modeling the multi-physics processes in the star-forming interstellar medium, including gravity, supernova feedback, magnetic fields, and galactic dynamics, with demonstrated convergence at 8pc resolution.

Contribution

We developed TIGRESS, a novel multi-physics simulation framework for the ISM, integrating key physical processes with verified convergence in a fiducial Solar neighborhood model.

Findings

TIGRESS accurately models star formation and supernova feedback.

Convergence achieved at 8pc resolution for key ISM properties.

The framework successfully reproduces observed ISM phases and dynamics.

Abstract

We introduce TIGRESS, a novel framework for multi-physics numerical simulations of the star-forming interstellar medium (ISM) implemented in the Athena MHD code. The algorithms of TIGRESS are designed to spatially and temporally resolve key physical features, including: (1) the gravitational collapse and ongoing accretion of gas that leads to star formation in clusters, (2) the explosions of supernovae (SNe) both near their progenitor birth sites and from runaway OB stars, with time delays relative to star formation determined by population synthesis, (3) explicit evolution of SN remnants prior to the onset of cooling, which leads to the creation of the hot ISM, (4) photoelectric heating of the warm and cold phases of the ISM that tracks the time-dependent ambient FUV field from the young cluster population, (5) large-scale galactic differential rotation, which leads to epicyclic motion and shears out overdense structures, limiting large-scale gravitational collapse, (6) accurate evolution of magnetic fields, which can be important for vertical support of the ISM disk as well as angular momentum transport. We present tests of the newly-implemented physics modules, and demonstrate application of TIGRESS in a fiducial model representing the Solar neighborhood environment. We use a resolution study to demonstrate convergence and evaluate the minimum resolution dx required to correctly recover several ISM properties, including the star formation rate, wind mass-loss rate, disk scale height, turbulent and Alfvenic velocity dispersions, and volume fractions of warm and hot phases. For the Solar neighborhood model, all these ISM properties are converged at dx <= 8pc.