IllustrisTNG in the HSC-SSP: No Shortage of Thin Disk Galaxies in TNG50

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 $z=0$ (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 $\Lambda$CDM models underproduced the abundance of thin galaxies. Specifically, for galaxies with stellar masses $10\le \log (M_{\star }/M_{\odot })\le 11.5$, we find $\lesssim 0.1\sigma$ tensions between the observations and the simulation, a stark contrast to the previously reported $\gtrsim 10\sigma$ tensions. We reveal that low-mass galaxies ($M_{\star }\lesssim 10^{9.5}{M}_{\odot }$) in TNG50 are thicker than their observed counterparts in HSC-SSP and attribute this to the spurious dynamical heating effects that artificially puff up galaxies. We also find that, despite the overall broad agreement, TNG50 galaxies are more concentrated than the HSC-SSP ones at the low- and high-mass end of the stellar mass range of $9.0\le \log (M_{\star }/M_{\odot })\le 11.2$ and are less concentrated at intermediate stellar masses. But we argue that the higher concentrations of the low-mass TNG50 galaxies are not likely the cause of their thicker/rounder appearances. Our study underscores the critical importance of conducting mock observations of simulations and applying consistent measurement methodologies to facilitate proper comparison with observations.

arXiv comment14 pages, 7 figures, published in ApJ

References in corpus (71)

• Planck 2015 results. XIII. Cosmological parameters
• Stellar population synthesis at the resolution of 2003
• The Sloan Digital Sky Survey: Technical Summary
• Galactic Stellar and Substellar Initial Mass Function
• On the variation of the Initial Mass Function
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Simulating Galaxy Formation with the IllustrisTNG Model
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• The Sixteenth Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
• Properties of galaxies reproduced by a hydrodynamic simulation
• Simulating galaxy formation with black hole driven thermal and kinetic feedback
• Galaxy and Mass Assembly (GAMA): survey diagnostics and core data release
• First Results from the TNG50 Simulation: Galactic outflows driven by supernovae and black hole feedback
• The Tenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic Evolution Experiment
• A model for cosmological simulations of galaxy formation physics
• First Results from the TNG50 Simulation: The evolution of stellar and gaseous disks across cosmic time
• Dancing in the dark: galactic properties trace spin swings along the cosmic web
• The Relationship Between Stellar Light Distributions of Galaxies and their Formation Histories
• Galaxy And Mass Assembly: Stellar Mass Estimates
• Gas-to-Dust mass ratios in local galaxies over a 2 dex metallicity range
• First Data Release of the Hyper Suprime-Cam Subaru Strategic Program
• Galaxy And Mass Assembly (GAMA): end of survey report and data release 2
• Structural Properties of Pseudo-Bulges, Classical Bulges and Elliptical Galaxies: an SDSS Perspective
• Second Data Release of the Hyper Suprime-Cam Subaru Strategic Program
• The Evolution of Galaxy Structure over Cosmic Time
• The optical morphologies of galaxies in the IllustrisTNG simulation: a comparison to Pan-STARRS observations
• Cosmological simulations of black hole growth: AGN luminosities and downsizing
• GEMS: Galaxy Evolution from Morphologies and SEDs
• The Kilo-Degree Survey
• GAMA: towards a physical understanding of galaxy formation
• Third Data Release of the Hyper Suprime-Cam Subaru Strategic Program
• A physical model for cosmological simulations of galaxy formation: multi-epoch validation
• Bulgeless Giant Galaxies Challenge our Picture of Galaxy Formation by Hierarchical Clustering
• Bulge n and B/T in High Mass Galaxies: Constraints on the Origin of Bulges in Hierarchical Models
• Connecting Angular Momentum and Galactic Dynamics: The complex Interplay between Spin, Mass, and Morphology
• The Hydrangea simulations: galaxy formation in and around massive clusters
• Galactic Angular Momentum in the Illustris Simulation: Feedback and the Hubble Sequence
• Morphology and star formation in IllustrisTNG: the build-up of spheroids and discs
• Geometry of Star-Forming Galaxies from SDSS, 3D-HST and CANDELS
• An HST/WFC3-IR Morphological Survey of Galaxies at z = 1.5-3.6: I. Survey Description and Morphological Properties of Star Forming Galaxies
• Galaxy Zoo: Dust in Spirals
• The Dragonfly Nearby Galaxies Survey. I. Substantial variation in the diffuse stellar halos around spiral galaxies
• Thin discs, thick dwarfs and the effects of stellar feedback
• Deep learning predictions of galaxy merger stage and the importance of observational realism
• Individual Stellar Halos of Massive Galaxies Measured to 100 kpc at $0.3<z<0.5$ using Hyper Suprime-Cam
• The shapes of galaxies in the Sloan Digital Sky Survey
• Structural Evolution of Early-type Galaxies to z=2.5 in CANDELS
• Galaxies in the Illustris simulation as seen by the Sloan Digital Sky Survey - II: Size-luminosity relations and the deficit of bulge-dominated galaxies in Illustris at low mass
• The SAMI Galaxy Survey: comparing 3D spectroscopic observations with galaxies from cosmological hydrodynamical simulations
• The Hubble Sequence at $z\sim 0$ in the IllustrisTNG simulation with deep learning
• The three phases of galaxy formation
• Convolutional neural network identification of galaxy post-mergers in UNIONS using IllustrisTNG
• The dust-continuum size of TNG50 galaxies at $z=1-5$: a comparison with the distribution of stellar light, stars, dust and H${}_2$
• Spurious heating of stellar motions in simulated galactic disks by dark matter halo particles
• The Intrinsic Shape of Galaxies in SDSS/Galaxy Zoo
• A constant limiting mass scale for flat early-type galaxies from z=1 to z=0: density evolves but shapes do not
• IllustrisTNG in the HSC-SSP: image data release and the major role of mini mergers as drivers of asymmetry and star formation
• Star Formation in Isolated Dwarf Galaxies Hosting Tidal Debris: Extending the Dwarf-Dwarf Merger Sequence
• AutoProf -- I. An automated non-parametric light profile pipeline for modern galaxy surveys
• Galaxies in the Illustris simulation as seen by the Sloan Digital Sky Survey - I: Bulge+disc decompositions, methods, and biases
• The Carnegie-Irvine Galaxy Survey. VIII. Demographics of Bulges along the Hubble Sequence
• The Carnegie-Irvine Galaxy Survey. VII. Constraints on the Origin of S0 Galaxies from Their Photometric Structure
• The Carnegie-Irvine Galaxy Survey. IX. Classification of Bulge Types and Statistical Properties of Pseudo Bulges
• Morphological signatures of mergers in the TNG50 simulation and the Kilo-Degree Survey: the merger fraction from dwarfs to Milky Way-like galaxies
• The impact of spurious collisional heating on the morphological evolution of simulated galactic discs
• The High Fraction of Thin Disk Galaxies Continues to Challenge ΛCDM Cosmology
• The combined and respective roles of imaging and stellar kinematics in identifying galaxy merger remnants
• Reaching for the Edge I: Probing the Outskirts of Massive Galaxies with HSC, DECaLS, SDSS, and Dragonfly
• ERGO-ML: Comparing IllustrisTNG and HSC galaxy images via contrastive learning
• The Carnegie-Irvine Galaxy Survey. X. Bulges in Stellar Mass-based Scaling Relations

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