Mock Observations: Morphological Analysis of Galaxies in TNG100 Simulations

Fuente: arXiv
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Main Authors: Gong, Jun-Yu, Lin, Weipeng, Tang, Lin, Lan, Yanyao
Format: Preprint
Published: 2025
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author Gong, Jun-Yu
Lin, Weipeng
Tang, Lin
Lan, Yanyao
author_facet Gong, Jun-Yu
Lin, Weipeng
Tang, Lin
Lan, Yanyao
contents In this study, we investigate the morphology of galaxies in the TNG100 simulation by applying mock observation techniques and compare the results with the observational data from the Sloan Digital Sky Survey (SDSS). By employing a hierarchical Convolutional Neural Network (CNN) approach, we classify galaxies into four morphological categories (Ellipticals, S0/a, Sab/Sb, and Sc/Sd/Irregulars). Our findings show that the morphological characteristics of the mock-observed galaxy samples closely match those observed in the SDSS, successfully reproducing key features such as distinct parameter distributions for different types. However, some discrepancies are identified: notably, a significant lack of early-type galaxies (ETGs) in the dwarf galaxy regime ($M_* < 10^{10} M_{\odot}$) and minimal distinction between Sab/Sb and Sc/Sd/Irregular galaxies in the mock-observed samples, unlike the clear differences seen in actual observations. These divergences may stem from simulation properties such as elevated star formation efficiency at low mass end or resolution limits. Observational effects, including the impact of the Point Spread Function, sky background, and instrumental noise, can independently cause approximately 7.87\% morphological misclassifications by our CNN model. Compared to previous studies using gravity-based definitions of galaxies that failed to clearly distinguish the parameter distributions of ETGs versus Late-Type Galaxies, our brightness-based sample definition method better recovers the observed morphological parameter distributions, especially their distinct differences. Our study underscores that, alongside mock observations, employing galaxy segmentation methods consistent with observational practices is crucial for appropriately recovering realistic morphological parameters from simulations and enabling fair comparisons.
format Preprint
id arxiv_https___arxiv_org_abs_2504_18042
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mock Observations: Morphological Analysis of Galaxies in TNG100 Simulations
Gong, Jun-Yu
Lin, Weipeng
Tang, Lin
Lan, Yanyao
Astrophysics of Galaxies
In this study, we investigate the morphology of galaxies in the TNG100 simulation by applying mock observation techniques and compare the results with the observational data from the Sloan Digital Sky Survey (SDSS). By employing a hierarchical Convolutional Neural Network (CNN) approach, we classify galaxies into four morphological categories (Ellipticals, S0/a, Sab/Sb, and Sc/Sd/Irregulars). Our findings show that the morphological characteristics of the mock-observed galaxy samples closely match those observed in the SDSS, successfully reproducing key features such as distinct parameter distributions for different types. However, some discrepancies are identified: notably, a significant lack of early-type galaxies (ETGs) in the dwarf galaxy regime ($M_* < 10^{10} M_{\odot}$) and minimal distinction between Sab/Sb and Sc/Sd/Irregular galaxies in the mock-observed samples, unlike the clear differences seen in actual observations. These divergences may stem from simulation properties such as elevated star formation efficiency at low mass end or resolution limits. Observational effects, including the impact of the Point Spread Function, sky background, and instrumental noise, can independently cause approximately 7.87\% morphological misclassifications by our CNN model. Compared to previous studies using gravity-based definitions of galaxies that failed to clearly distinguish the parameter distributions of ETGs versus Late-Type Galaxies, our brightness-based sample definition method better recovers the observed morphological parameter distributions, especially their distinct differences. Our study underscores that, alongside mock observations, employing galaxy segmentation methods consistent with observational practices is crucial for appropriately recovering realistic morphological parameters from simulations and enabling fair comparisons.
title Mock Observations: Morphological Analysis of Galaxies in TNG100 Simulations
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2504.18042