TwoPhaseGalaxyModel - a Two-Phase Scenario of Galaxy Formation

This repository contains the code of the semi-analytic implementation of the TwoPhaseGalaxyModel. All data and figures in the publications are also included in the repository.

Installation

To install, run:

pip install two-phase-galaxy-model

All the dependencies will be installed automatically. Alternatively, you can clone the repository and install the package locally via pip install -e /path/to/the/repo.

Usage

To use the API in your Python project, import the package by:

import two_phase_galaxy_model as tpgm

and then work with it.

Examples can be found in the Jupyter notebooks under docs/:

• star_cluster_model.ipynb: demonstrates how to define a dark-matter-only subhalo merger tree, pass it to the model, and get the list of galaxies and star clusters.

Publications

List of publications

• (Paper-I) A two-phase model of galaxy formation: I. The growth of galaxies and supermassive black holes. Houjun Mo, Yangyao Chen, and Huiyuan Wang, 2023 (arxiv, ads).
• (Paper-II) A two-phase model of galaxy formation: II. The size-mass relation of dynamically hot galaxies. Yangyao Chen, Houjun Mo, and Huiyuan Wang, 2023 (arxiv, ads).
• (Paper-III) A two-phase model of galaxy formation: III. The formation of globular clusters. Yangyao Chen, Houjun Mo, and Huiyuan Wang, 2024 (arxiv, ads).

Supplementary Material

• Paper-I: figures in the pdf format.
• Paper-II: figures in the pdf format.
• Paper-III: figures in the pdf format.

Research Highlights

The phase diagram of galaxy formation and SMBH growth

Left: The quadrant diagram showing four combinations of halo assembly rate and the importance of angular momentum in supporting gas. Center: The formation of dynamically hot gas/stellar system in the fast stage of dark matter halo. Right: A schematic diagram showing the distribution of specific angular momentum (sAM) for gas clouds within a halo. The turbulent motion of gas clouds, driven by fast accretion, yields a broad and uniform distribution (red curve) of sAM. The fraction of gas accreted by the SMBH (gray shaded area) is determined by the maximum capturing angular momentum (see Paper-I).

The two-channels of GC formation

Left: The distribution of modeled GCs in a MW-size system at z=0. Right: The criteria for the active formation of Pop-I (red, metal-rich) and Pop-II (blue, metal-poor) GCs in the halo mass-redshift plane (See Paper-III).

Cosmic structures traced by GC clustering over > 7 orders of magnitude in spatial extent

Two-point auto-correlation functions of GCs at z=0 predicted by the model in this work and the corresponding gas process and cosmic structure at each hierarchy (See Paper-III).

Acknowledgements

Here we acknowledge the following projects and/or people that helped in the development of this code repository. Projects and/or people that are relevant to individual papers were included in the papers.

Yangyao thanks Kai Wang for his enduring companionship and support :wink:.

The empirical model UniverseMachine for halo-galaxy connection, and TRINITY for halo-galaxy-SMBH coevolution, have inspired our work for model design and implementation. Their comprehensive collection of observational datasets also helps us for model calibration and comparison.

The SAM of Yingtian Chen, Oleg Y. Gnedin et al. (source code) and the catalog produced by the model have been used for comparison of our model.

The Tsinghua Astrophysics High-Performance Computing platform has been providing the computational and data storage resources throughout the career development of Yangyao.