Statistics of galaxy mergers: bridging the gap between theory and observation

Abstract

We present a study of galaxy mergers up to $z=10$ using the Planck Millennium cosmological dark matter simulation and the {\tt GALFORM} semi-analytical model of galaxy formation. Utilising the full ($800$ Mpc)${}^3$ volume of the simulation, we studied the statistics of galaxy mergers in terms of merger rates and close pair fractions. We predict that merger rates begin to drop rapidly for high-mass galaxies ($M_{\ast }>10^{11.3}-10^{10.5}$ $M_{\odot }$ for $z=0-4$), as a result of the exponential decline in the galaxy stellar mass function. The predicted merger rates increase and then turn over with increasing redshift, by $z=3.5$, in disagreement with hydrodynamical simulations and semi-empirical models. In agreement with most other models and observations, we find that close pair fractions flatten or turn over at some redshift (dependent on the mass selection). We conduct an extensive comparison of close pair fractions, and highlight inconsistencies among models, but also between different observations. We provide a fitting formula for the major merger timescale for close galaxy pairs, in which the slope of the stellar mass dependence is redshift dependent. This is in disagreement with previous theoretical results that implied a constant slope. Instead we find a weak redshift dependence only for massive galaxies ($M_{\ast }>10^{10}$ M${}_{\odot }$): in this case the merger timescale varies approximately as $M_{\ast }^{-0.55}$. We find that close pair fractions and merger timescales depend on the maximum projected separation as $r_{\max }^{1.32}$. This is in agreement with observations of small-scale clustering of galaxies, but is at odds with the linear dependence on projected separation that is often assumed.

arXiv commentAccepted for publication in MNRAS

References in corpus (96)

• Planck 2013 results. XVI. Cosmological parameters
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• The broken hierarchy of galaxy formation
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Simulating Galaxy Formation with the IllustrisTNG Model
• Hierarchical Galaxy Formation
• Gasdynamics and Starbursts in Major Mergers
• Galactic star formation and accretion histories from matching galaxies to dark matter haloes
• UniverseMachine: The Correlation between Galaxy Growth and Dark Matter Halo Assembly from z=0-10
• Mass assembly in quiescent and star-forming galaxies since z=4 from UltraVISTA
• The Assembly and Merging History of Supermassive Black Holes in Hierarchical Models of Galaxy Formation
• The Evolution of the Stellar Mass Functions of Star-Forming and Quiescent Galaxies to z = 4 from the COSMOS/UltraVISTA Survey
• Minor mergers and the size evolution of elliptical galaxies
• Resolving Cosmic Structure Formation with the Millennium-II Simulation
• Dancing in the dark: galactic properties trace spin swings along the cosmic web
• Galaxy Clustering in the Completed SDSS Redshift Survey: The Dependence on Color and Luminosity
• The merger rate of galaxies in the Illustris Simulation: a comparison with observations and semi-empirical models
• Galaxy formation in the Planck Cosmology - I. Matching the observed evolution of star formation rates, colours and stellar masses
• A primer on hierarchical galaxy formation: the semi-analytical approach
• The stellar mass assembly of galaxies in the Illustris simulation: growth by mergers and the spatial distribution of accreted stars
• The Evolution of Galaxy Mergers and Morphology at z<1.2 in the Extended Groth Strip
• Can Minor Merging Account for the Size Growth of Quiescent Galaxies? New Results from the CANDELS Survey
• Mergers and Bulge Formation in Lambda-CDM: Which Mergers Matter?
• The Major and Minor Galaxy Merger Rates at z < 1.5
• Galaxy Merger Morphologies and Time-Scales from Simulations of Equal-Mass Gas-Rich Disc Mergers
• EMERGE - An empirical model for the formation of galaxies since $z\sim 10$
• A unified multi-wavelength model of galaxy formation
• Dynamical Friction and Galaxy Merging Timescales
• Major Galaxy Mergers Only Trigger the Most Luminous AGN
• Galaxy and Mass Assembly (GAMA): The GAMA Galaxy Group Catalogue (G3Cv1)
• Galaxy And Mass Assembly (GAMA): The galaxy stellar mass function at z < 0.06
• Galaxy Groups in the SDSS DR4: III. the luminosity and stellar mass functions
• The dependence of clustering on galaxy properties
• A fitting formula for the merger timescale of galaxies in hierarchical clustering
• The Greater Impact of Mergers on the Growth of Massive Galaxies: Implications for Mass Assembly and Evolution Since z~1
• The Effect of Mass Ratio on the Morphology and Time-scales of Disc Galaxy Mergers
• The Redshift Evolution of Wet, Dry, and Mixed Galaxy Mergers from Close Galaxy Pairs in the DEEP2 Galaxy Redshift Survey
• Mergers in Lambda-CDM: Uncertainties in Theoretical Predictions and Interpretations of the Merger Rate
• The Structures of Distant Galaxies I: Galaxy Structures and the Merger Rate to z~3 in the Hubble Ultra-Deep Field
• Galaxy growth in the concordance $\Lambda$CDM cosmology
• A calibration of the relation between the abundance of close galaxy pairs and the rate of galaxy mergers
• Early and Rapid Merging as a Formation Mechanism of Massive Galaxies: Empirical Constraints
• A definitive merger-AGN connection at z~0 with CFIS: mergers have an excess of AGN and AGN hosts are more frequently disturbed
• A chronicle of galaxy mass assembly in the EAGLE simulation
• The VIMOS VLT Deep Survey :Evolution of the major merger rate since z~1 from spectroscopicaly confirmed galaxy pairs
• The Effect of Gas Fraction on the Morphology and Time-scales of Disc Galaxy Mergers
• A new model of galaxy formation: How sensitive are predicted galaxy luminosities to the choice of SPS model?
• Observational constraints on the merger history of galaxies since $z\approx 6$: Probabilistic galaxy pair counts in the CANDELS fields
• The Structures of Distant Galaxies - III: The Merger History of over 20,000 Massive Galaxies at z < 1.2
• The structures and total (minor + major) merger histories of massive galaxies up to z = 3 in the HST GOODS NICMOS Survey: A possible solution to the size evolution problem
• How well can we really estimate the stellar masses of galaxies from broadband photometry?
• Galaxy And Mass Assembly (GAMA): Galaxy close-pairs, mergers, and the future fate of stellar mass
• Quantifying the impact of mergers on the angular momentum of simulated galaxies
• The dominant role of mergers in the size evolution of massive early-type galaxies since z ~ 1
• The Millennium Galaxy Catalogue: The connection between close pairs and asymmetry; implications for the galaxy merger rate
• Galaxy Mergers and Dark Matter Halo Mergers in LCDM: Mass, Redshift, and Mass-Ratio Dependence
• Resolving the Discrepancy of Galaxy Merger Fraction Measurements at z ~ 0 - 3
• Galaxy Pairs in COSMOS -- Merger Rate Evolution Since z=1
• A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at $z<3.5$
• Stellar mass functions: methods, systematics and results for the local Universe
• Galaxy morphology in the LambdaCDM cosmology
• The evolution of the galaxy stellar mass function over the last twelve billion years from a combination of ground-based and HST surveys
• Galaxy formation in the Planck Millennium: the atomic hydrogen content of dark matter halos
• Galaxy And Mass Assembly (GAMA): Refining the Local Galaxy Merger Rate using Morphological Information
• The merger-driven evolution of massive galaxies
• The diminishing importance of major galaxy mergers at higher redshifts
• The remnant of a merger between two dwarf galaxies in Andromeda II
• Massive Close Pairs Measure Rapid Galaxy Assembly in Mergers at High Redshift
• The VIMOS VLT Deep Survey - The evolution of galaxy clustering to z=2 from first epoch observations
• Major Merging History in CANDELS. I. Evolution of the Incidence of Massive Galaxy-Galaxy Pairs from z=3 to z~0
• The MUSE Hubble Ultra Deep Field Survey. IX. Evolution of galaxy merger fraction since z~6
• Galaxy Mergers at z>1 in the HUDF: Evidence for a Peak in the Major Merger Rate of Massive Galaxies
• The VIMOS VLT Deep Survey: the contribution of minor mergers to the growth of L_B >= L*_B galaxies since z ~ 1 from spectroscopically identified pairs
• The host galaxies of X-ray selected Active Galactic Nuclei to z=2.5: Structure, star-formation and their relationships from CANDELS and Herschel/PACS
• Galaxy and Mass Assembly (GAMA): Projected Galaxy Clustering
• Minor vs Major Mergers: The Stellar Mass Growth of Massive Galaxies from z=3 using Number Density Selection Techniques
• GAMA/G10-COSMOS/3D-HST: Evolution of the galaxy stellar mass function over 12.5Gyrs
• Galaxy disks do not need to survive in the L-CDM paradigm: the galaxy merger rate out to z~1.5 from morpho-kinematic data
• Constraints on the merging channel of massive galaxies since z~1
• The merger rates and sizes of galaxies across the peak epoch of star formation from the HiZELS survey
• Galaxy merger histories and the role of merging in driving star formation at z>1
• EMERGE: Empirical predictions of galaxy merger rates since $z\sim 6$
• New criteria for the selection of galaxy close pairs from cosmological simulations: evolution of the major and minor merger fraction in MUSE deep fields
• A Hubble Space Telescope Snapshot Survey of Dynamically Close Galaxy Pairs in the CNOC2 Redshift Survey
• The Structures of Distant Galaxies - IV: A New Empirical Measurement of the Time-Scale for Galaxy Mergers - Implications for the Merger History
• The ALHAMBRA survey: Accurate merger fractions by PDF analysis of photometric close pairs
• The Diffusion Approximation vs. the Telegraph Equation for Modeling Solar Energetic Particle Transport with Adiabatic Focusing. I. Isotropic Pitch-angle Scattering
• Modelling Galaxy Merger Timescales and Tidal Destruction
• Quenching and anisotropy of hydromagnetic turbulent transport
• A scaling relation between merger rate of galaxies and their close pair count
• Connections between galaxy mergers and Starburst: evidence from local Universe
• Small-scale galaxy clustering in the EAGLE simulation
• Clustering with JWST: Constraining Galaxy Host Halo Masses, Satellite Quenching Efficiencies, and Merger Rates at z=4-10
• Formation and assembly history of stellar components in galaxies as a function of stellar and halo mass
• 2MASS/SDSS Close Major-Merger Galaxy Pairs: Luminosity Functions and Merger Mass Dependence

Cited by in corpus (25)

• Born this way: thin disc, thick disc, and isotropic spheroid formation in FIRE-2 Milky-Way-mass galaxy simulations
• A direct measurement of galaxy major and minor merger rates and stellar mass accretion histories at $z<3$ using galaxy pairs in the REFINE survey
• Galaxy Mergers in the Epoch of Reionization I: A JWST Study of Pair Fractions, Merger Rates, and Stellar Mass Accretion Rates at $z=4.5-11.5$
• Morphological signatures of mergers in the TNG50 simulation and the Kilo-Degree Survey: the merger fraction from dwarfs to Milky Way-like galaxies
• VINTERGATAN IV: Cosmic phases of star formation in Milky Way-like galaxies
• The dawn of disks: unveiling the turbulent ionised gas kinematics of the galaxy population at $z\sim 4-6$ with JWST/NIRCam grism spectroscopy
• The buildup of galaxies and their spheroids: the contributions of mergers, disc instabilities and star formation
• Galaxy merger challenge: A comparison study between machine learning-based detection methods
• Massive Early-Type Galaxies in the HSC-SSP: Flux Fraction of Tidal Features and Merger Rates
• Probing the Merger Rates of Supermassive Black Holes and Galaxies with Gravitational Waves
• The molecular gas resolved by ALMA in the low-metallicity dwarf merging galaxy Haro 11
• Dynamics and spin alignment in massive, gravito-turbulent circumbinary discs around supermassive black hole binaries
• Obscured AGN enhancement in galaxy pairs at cosmic noon: evidence from a probabilistic treatment of photometric redshifts
• Probing the Delay Time of Supermassive Black Hole Binary Mergers With Gravitational Waves
• JWST + ALMA ubiquitously discover companion systems within $\lesssim 18$kpc around four $z$$\approx$3.5 luminous radio-loud AGN
• Halo Growth and Merger Rates as a Cosmological Test
• Galaxy pairs in The Three Hundred simulations: a study on the performance of observational pair-finding techniques
• The Most Massive Early-type Galaxies Exhibit Tidal Features More Frequently in Lower-density Environments
• The PAU Survey: Close galaxy pairs identification and analysis
• Galaxy pairs in The Three Hundred simulations II: studying bound ones and identifying them via machine learning
• DARKSKIES: A suite of super-sampled zoom-in simulations of galaxy clusters with self-interacting dark matter
• The JWST Emission Line Survey (JELS): The sizes and merger fraction of star-forming galaxies during the Epoch of Reionization
• Stellar Stripping and Disruption in Disks around Supermassive Black Hole Binaries: Repeating nuclear transients prior to LISA events
• On the Origins of "Hostless'' Supernovae: Testing the Faint-end Galaxy Luminosity Function and Supernova Progenitors with Events in Dwarf Galaxies
• Gas-rich dwarf galaxy multiples in the Apertif HI survey