IllustrisTNG in the HSC-SSP: No Shortage of Thin Disk Galaxies in TNG50
Dewang Xu, Hua Gao, Connor Bottrell, Hassen M. Yesuf, Jingjing Shi

TL;DR
This study compares the shapes of galaxies in the TNG50 simulation with real observations from HSC-SSP, finding excellent agreement for certain mass ranges and highlighting the importance of mock observations for accurate comparisons.
Contribution
It introduces a forward-modeling approach for shape comparison, demonstrating that TNG50 accurately reproduces the abundance of thin disk galaxies in the observed universe.
Findings
Excellent agreement between TNG50 and observations for galaxies with $10 \,\leq\, \log (M_{\star}/M_{\odot}) \leq 11.5$.
Low-mass TNG50 galaxies are thicker than observed, likely due to dynamical heating effects.
TNG50 galaxies are more concentrated at low and high masses but less at intermediate masses.
Abstract
We perform a thorough analysis of the projected shapes of nearby galaxies in both observations and cosmological simulations. We implement a forward-modeling approach to overcome the limitations in previous studies, which hinder accurate comparisons between observations and simulations. We measure axis ratios of (snapshot 99) TNG50 galaxies from their synthetic Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) images and compare them with those obtained from real HSC-SSP images of a matched galaxy sample. Remarkably, the comparison shows excellent agreement between the observations and the TNG50 simulation, challenging previous claims that CDM models underproduced the abundance of thin galaxies. Specifically, for galaxies with stellar masses , we find tensions between the observations and the simulation,…
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Taxonomy
TopicsAstronomy and Astrophysical Research · Galaxies: Formation, Evolution, Phenomena · Astrophysical Phenomena and Observations
