Torch

Torch is a code to simulate coupled gas and N-body dynamics in astrophysical systems such as newly forming star clusters. It combines the FLASH code for gas dynamics and the ph4 code for direct N-body evolution via the AMUSE framework. An introduction to Torch is given by Wall et al. 2019ApJ...887...62W and 2020ApJ...904..192W, as well as Joshua Wall's Ph.D thesis (pdf mirror).

Torch is distributed as an open-source Bitbucket repository. It is a new code in active development; contributions and bug reports are welcome.

To start using Torch, here is a quickstart guide adapted from a workshop held 2019 August 28-30.

You can join the Torch mailing list to discuss Torch usage and development.

There are several research papers that utilize the Torch framework.

Pre-print:

• Cournoyer-Cloutier et al. (2024b): Massive Star Cluster Formation with Binaries I. Evolution of Binary Populations
• Polak et al. (2024c): Massive star cluster formation III. Early mass segregation during cluster assembly
• Polak et al. (2024b): Massive Star Cluster Formation II. Runaway Stars as Fossils of Sub-Cluster Mergers

• Polak et al. (2024a): Massive star cluster formation: I. High star formation efficiency while resolving feedback of individual stars
• Cournoyer-Cloutier et al. (2023): Early evolution and three-dimensional structure of embedded star clusters
• Wilhelm et al. (2023): Radiation shielding of protoplanetary discs in young star-forming regions
• Lewis et al. (2023): Early-forming massive stars supress star formation and heirarchical cluster assembly
• Cournoyer-Cloutier et al. (2021): Implementing primordial binaries in simulations of star cluster formation with a hybrid MHD and direct N-body method
• Wall et al. (2020): Modeling the effects of stellar feedback during star cluster formation using a hybrid gas and N-body method
• Wall et al. (2019): Collisional N-body dynamics coupled to self-gravitating magnetohydrodynamics reveals dynamical binary formation

Torch simulations are also used as initial conditions for N-body and hydrodynamics simulations.

Published:

• Cournoyer-Cloutier et al. (2024a): Binary Disruption and Ejected Stars from Hierarchical Star Cluster Assembly

Torch is a central part of several PhD and MSc theses:

• Joshua E. Wall (PhD, 2019): The Formation and Early Evolution of Stellar Clusters
• Claude Cournoyer-Cloutier (MSc, 2021): Dynamical Modification of a Primordial Population of Binaries in Simulations of Star Cluster Formation
• Sabrina M. Appel (PhD, 2024): Exploring the effect of protostellar feedback on star formation and molecular cloud dynamics

The Torch project is supported by NASA grant no. NNX14AP27G and NSF grant no. 1815461.