Identification of Compact Groups of Galaxies in IllustrisTNG300

Abstract

We identify compact groups of galaxies (CGs) in the IllustrisTNG-300 simulation using a Friends-of-Friends (FoF) algorithm. Our approach is designed to be comparable to systematic CG searches based on spectroscopic surveys, while avoiding the conventional Hickson selection criteria, which can bias samples toward relatively low-density environments. We construct two CG catalogs: one based on a three-dimensional distance linking length of 73 kpc (i.e., $50h^{-1}$ kpc), and another based on projected and radial linking lengths of 73 kpc and $1000\mathrm{km}{\mathrm{s}}^{-1}$. We refer to these as the position-position-position (PPP) and position-position-velocity (PPV) CG catalogs, respectively. The PPV catalog provides a direct analog to observed CG samples. At $z=0$ in TNG300, we identify 383 PPP CGs and 1666 PPV CGs. A large fraction ($\sim 80\%$) of PPV CGs are not physically compact systems but are contaminated by line-of-sight interlopers. We demonstrate that the scaling relation between total group stellar mass and velocity dispersion is an effective diagnostic for identifying false positives with line-of-sight interlopers. We further examine the large-scale environments of CGs and show that they reside in a wide range of densities, including the central regions of galaxy clusters. These CG catalogs provide a robust foundation for studying the formation and evolution of CGs in cosmological simulations.

References in corpus (41)

• Populating a cluster of galaxies - I. Results at z=0
• First results from the IllustrisTNG simulations: matter and galaxy clustering
• First results from the IllustrisTNG simulations: the stellar mass content of groups and clusters of galaxies
• Accurate photometric redshifts for the CFHT Legacy Survey calibrated using the VIMOS VLT Deep Survey
• First results from the IllustrisTNG simulations: the galaxy color bimodality
• First results from the IllustrisTNG simulations: A tale of two elements -- chemical evolution of magnesium and europium
• First results from the IllustrisTNG simulations: radio haloes and magnetic fields
• Measuring and Modelling the Redshift Evolution of Clustering: the Hubble Deep Field North
• Detecting Bimodality in Astronomical Datasets
• Galaxy and Mass Assembly (GAMA): The GAMA Galaxy Group Catalogue (G3Cv1)
• Virial Scaling of Massive Dark Matter Halos: Why Clusters Prefer a High Normalization Cosmology
• A ROSAT survey of Hickson's compact galaxy groups
• Where is the Neutral Atomic Gas in Hickson Groups?
• Effects of Interaction Induced Activities in Hickson Compact Groups: CO and FIR Study
• Compact Group Selection From Redshift Surveys
• Galaxy Evolution in Hickson Compact Groups: The Role of Ram Pressure Stripping and Strangulation
• Evolution of Compact Groups of Galaxies I. Merging Rates
• Compact groups in theory and practice - III. Compact groups of galaxies in the Sixth Data Release of the Sloan Digital Sky Survey
• HeCS-SZ: The Hectospec Survey of Sunyaev-Zeldovich Selected Clusters
• A Catalog of Compact Groups of Galaxies in the SDSS Commissioning Data
• The Scaling of Stellar Mass and Central Stellar Velocity Dispersion for Quiescent galaxies at z < 0.7
• Friends-of-friends galaxy group finder with membership refinement. Application to the local Universe
• Compact Groups of Galaxies selected by stellar mass: The 2MASS Compact Group Catalogue
• Where are compact groups in the local Universe?
• A Catalog of Distant Compact Groups Using DPOSS
• The Optical Green Valley vs Mid-IR Canyon in Compact Groups
• Compact groups in theory and practice -- IV. The connection to large-scale structure
• Compact Groups of Galaxies with Complete Spectroscopic Redshifts in the Local Universe
• Catalogs of Compact Groups of Galaxies from the Enhanced SDSS DR12
• Studying the evolution of galaxies in compact groups over the past 3 Gyr - II. The importance of environment in the suppression of star formation
• The Velocity Dispersion Function for Quiescent Galaxies in the Local Universe
• The HectoMAP Redshift Survey: First Data Release
• Compact Groups of Galaxies in Sloan Digital Sky Survey and LAMOST Spectral Survey: I. The Catalogs
• Galaxy triplets in Sloan Digital Sky Survey Data Release 7: II. A connection with compact groups?
• Improving Hickson-like compact group finders in redshift surveys: an implementation in the SDSS
• The DPOSS II distant compact group survey: the EMMI-NTT spectroscopic sample
• The Fastest Galaxy Evolution in an Unbiased Compact Group Sample with WISE
• Compact groups from semi-analytical models of galaxy formation -- I: a comparative study of frequency and nature
• Abundance and group coalescence timescales of compact groups of galaxies in the EAGLE simulation
• The influence of Hickson-like compact group environment on galaxy luminosities
• Compact groups of galaxies in GAMA -- Probing the densest minor systems at intermediate redshifts