TIGRESS, a numerical framework for

Three phase ISM in Galaxies Resolving Evolution with Star formation and Supernova feedback

Core Developers: Chang-Goo Kim and Eve Ostriker

TIGRESS framework

The TIGRESS code is built on the Athena MHD code package with additional physical modules.

TIGRESS + Radiation/Chemistry

New TIGRESS framework develompent with radiation and chemistry with Jeong-Gyu Kim and Munan Gong

TIGRESS + Spiral Arms

TIGRESS extension to spiral arm coordinates with Woong-Tae Kim

TIGRESS + Bar Inflows

TIGRESS extension to galactic center models with bar-driven inflows with Sanghyuk Moon and Woong-Tae Kim

TIGRESS + ICM

TIGRESS extension to model multiphase ISM interacting with ICM winds with Woorak Choi and Aeree Chung

Multiphase Outflows

Large scale outflows in star-forming galaxies are observed to be ubiquitous, and are a key aspect of theoretical modeling of galactic evolution in a cosmological context. Gas blown out from galactic disks, similar to gas within galaxies, consists of multiple phases with large contrasts of density, temperature, and other properties. To study multiphase outflows as emergent phenomena, we run a suite of ~pc-resolution local galactic disk simulations using the TIGRESS framework. Explicit modeling of the interstellar medium (ISM), including star formation and self-consistent radiative heating plus supernova feedback, regulates ISM properties and drives the outflow. The main components of outflowing gas are mass-delivering cool gas (T~104K) and energy/metal-delivering hot gas (T~106K). Cool mass outflow rates measured at outflow launch points (one or two scale heights) are 1--100 times the SFR (decreasing with ΣSFR), although in massive galaxies most mass falls back due to insufficient outflow velocity. The hot galactic outflow carries mass comparable to 10% of the SFR, together with with 10-20% of the energy and 30-60% of the metal mass injected by SN feedback. The characteristic outflow velocities of both phases scale very weakly with SFR, as vout∝ΣSFR0.1-0.2, consistent with observations. Importantly, our analysis demonstrates that in any physically-motivated cosmological wind model, it is crucial to include two distinct thermal wind components.


Multiphase Outflow Characterization and Scaling Relations with Galactic Properties

A comprehensive characterization of multiphase galactic outflows from a suite of TIGRESS simulations in the context of the SMAUG (Simulating Multiscale Astrophysics to Understand Galaxies) project. We investigate the scaling of outflow mass, momentum, energy, and metal loading factors with galactic disk properties, including star formation rate (SFR) surface density (ΣSFR), gas surface density, and total pressure (or weight).

Twind: TIGRESS Multiphase Galactic Wind Launching Model

Outflow mass flux distribution is characterized as continua in the outflow velocity (vout) and sound speed (cs) phase plane. We present a flexible, light-weighted parameterized model of the joint PDF for physically-motivated subgrid outflow model in cosmological simulations.

Hot Winds and Cool Fountains in the Solar Neighborhood Model

Multiphase outflow anaylsis of the Solar neighborhood TIGRESS model, including phase-separated investigations of mass, momentum, and energy flux profiles as well as velocity distributions.

Multiphase Outflow Interaction

Flux exchanges in the extraplanar region (1kpc<z<3kpc) between different phase outlfows are quantified. The cool fountain flow (T~104K) gains mass flux from the intermediate phase (T~105K) and momentum/energy flux from the hot wind (T≥106K).

Self-regulation of Star Formation Rates

Star formation rates are self-regulated until star formation feedback modulated pressure provides support against the disk weight. The theory refined with the TIGRESS simulation suite is in preparation (Ostriker & CG Kim).

Standard TIGRESS Suite

Ostriker & CG Kim (in prep.)

Spiral Arm Models

WT Kim, CG Kim, Ostriker

Galactic Center Models

Moon, WT Kim, CG Kim, Ostriker (in prep.)

Ram Pressure Stripping Models

Choi, Kim, Chung (in prep.)

Cloud scale properties and SFRs

Mao, Ostriker, Kim

Observable Properties of TIGRESS

Dust Polarization

Polarized Dust Emission from TIGRESS as CMB foreground templates

Post-Processing Molecular Chemistry

CO-H2 conversion factor

Post-Processing Ionizing Radiation

Diffuse Ioinized Gas

Lyman-Alpha Radiation Trasfer: LaRT

Post-processing of TIGRESS snapshots using LaRT to understand the WF effect on HI 21cm line excitation.