Constructing a Mock Galaxy Catalog for the All-sky SPECtroscopic Survey of Nearby Galaxies (A-SPEC) Using the Machine-assisted Semi-Simulation Model

arXiv:2607.06933 · astro-ph.CO · Submitted 2026-07-08 · Read on arXiv

Dongkok Kim, Yongseok Jo, Ho Seong Hwang, Ji-hoon Kim, Juhan Kim, Jaehyun Lee, Hyeonguk Bahk, Young-Man Choi, Moo-Young Chun, Sang-Hyun Chun, Haeun Chung, Kim Dachan, Sungwook E. Hong, Minhee Hyun, Donghui Jeong, Jae-Woo Kim, Kang-Min Kim, Yunjong Kim, Jongwan Ko, Minseong Kwon, Ho-Gyu Lee, Jong Chul Lee, Yongseok Lee, Hyunho Lim, Heeyoung Oh, Changbom Park, Hyunmi Song, Mingyeong Yang, Yongmin Yoon

astro-ph.CO

Submitted: 2026-07-08

Comments: Accepted for publication in ApJS. 34 pages, 22 figures. Mock catalog available at https://doi.org/10.5281/zenodo.21140927

License: http://creativecommons.org/licenses/by/4.0/

The gist: We present a methodology for constructing a mock galaxy catalog for the All-sky SPECtroscopic survey of nearby galaxies (A-SPEC) using the Machine-assisted Semi-Simulation Model.

Terminology

Clustering — 18× in this paper · explained in 2 episodes
Accuracy — 12× in this paper · explained in 1 episode
Aperture — 12× in this paper · explained in 1 episode
Metallicity — 11× in this paper · explained in 3 episodes
Anisotropy — 10× in this paper · explained in 3 episodes
Seoul National University — 5× in this paper
SHAP values — 4× in this paper · explained in 2 episodes
Abundance — 3× in this paper · explained in 1 episode
Korea Astronomy and Space Science Institute — 3× in this paper
National Research Foundation of Korea — 3× in this paper
AGN — 2× in this paper · explained in 1 episode
Fine-Tuning — 2× in this paper · explained in 5 episodes
Generalization — 2× in this paper · explained in 13 episodes
Velocity Dispersion — 2× in this paper · explained in 2 episodes
AGN Feedback — 1× in this paper · explained in 1 episode
Active Galactic Nuclei (AGN) — 1× in this paper · explained in 1 episode
Consistency — 1× in this paper · explained in 3 episodes
Hubble Tension — 1× in this paper · explained in 9 episodes
N-body simulations — 1× in this paper · explained in 2 episodes
Selection Bias — 1× in this paper · explained in 4 episodes
Siding Spring Observatory — 1× in this paper
Star Formation Rate (SFR) — 1× in this paper · explained in 5 episodes
Systematic Bias — 1× in this paper · explained in 3 episodes
Trace — 1× in this paper · explained in 2 episodes

Abstract

We present a methodology for constructing a mock galaxy catalog for the All-sky SPECtroscopic survey of nearby galaxies (A-SPEC) using the Machine-assisted Semi-Simulation Model. The model is trained on the cosmological magnetohydrodynamical simulation IllustrisTNG to predict baryonic properties of subhalos from dark-matter-only features and is applied to our own N-body simulation tailored to satisfy the requirements of A-SPEC. We have improved the model's accuracy by introducing additional features such as subhalo anisotropy parameters and modified definitions of the subhalo environment, which result in the coefficient of determination R 2=0.96, 0.90, 0.70, 0.79 for stellar mass, gas mass, star formation rate, and gas metallicity, respectively. The resulting mock galaxies reproduce the luminosity-dependent clustering of the target galaxies when tuned to match the number density. We discuss avenues for further improvement, including the role of environment in the predictions. We release the mock galaxy catalog with the baryonic properties predicted from the model.

Constructing a Mock Galaxy Catalog for the All-sky SPECtroscopic Survey of Nearby Galaxies (A-SPEC) Using the Machine-assisted Semi-Simulation Model

Terminology

Abstract

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