Galaxy Mergers in the Epoch of Reionization II: Major Merger-Triggered Star Formation and AGN Activities at $z=$ 4.5-8.5

Abstract

Galaxy mergers are a key driver of galaxy formation and evolution, including the triggering of AGN and star formation to a still unknown degree. We thus investigate the impact of galaxy mergers on star formation and AGN activity using a sample of 3,330 galaxies at $z=[4.5,8.5]$ from eight JWST fields (CEERS, JADES GOODS-S, NEP-TDF, NGDEEP, GLASS, El-Gordo, SMACS-0723, and MACS-0416), collectively covering an unmasked area of 189 arcmin${}^2$. We focuses on star formation rate (SFR) enhancement, AGN fraction, and AGN excess in major merger ($\mu >1/4$) close-pair samples, defined by $\Delta z<0.3$ and projected separations $r_p<100$ kpc, compared to non-merger samples. We find that SFR enhancement occurs only at $r_p<20$ kpc, with values of $0.25\pm 0.10$ dex and $0.26\pm 0.11$ dex above the non-merger medians for $z=[4.5,6.5]$ and $z=[6.5,8.5]$. No other statistically significant enhancements in galaxy sSFR or stellar mass are observed at any projected separation or redshift bin. We also compare our observational results with predictions from the SC-SAM simulation and find no evidence of star formation enhancement in the simulations at any separation range. Finally, we examine the AGN fraction and AGN excess, finding that the fraction of AGNs in AGN-galaxy pairs, relative to the total AGN population, is $3.25_{-1.06}^{+1.50}$ times greater than the fraction of galaxy pairs relative to the overall galaxy population at the same redshift. We find that nearly all AGNs have a companion within 100 kpc and observe an excess AGN fraction in close-pair samples compared to non-merger samples. This excess is found to be $1.26\pm 0.06$ and $1.34\pm 0.06$ for AGNs identified via the inferred BPT diagram and photometric SED selection, respectively.

17 Pages, 7 Figures, Submitted to MNRAS

References in corpus (100)

• Array Programming with NumPy
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• The Host Galaxies and Classification of Active Galactic Nuclei
• EAZY: A Fast, Public Photometric Redshift Code
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• Introducing the Illustris Project: the evolution of galaxy populations across cosmic time
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• Galaxy Pairs in the Sloan Digital Sky Survey I: Star Formation, AGN Fraction, and the Luminosity/Mass-Metallicity Relation
• CEERS Key Paper I: An Early Look into the First 500 Myr of Galaxy Formation with JWST
• Star formation efficiency in galaxy interactions and mergers: a statistical study
• Two Remarkably Luminous Galaxy Candidates at $z\approx 10-12$ Revealed by JWST
• The Science Performance of JWST as Characterized in Commissioning
• The evolution of the galaxy UV luminosity function at redshifts z ~ 8-15 from deep JWST and ground-based near-infrared imaging
• Galaxy Merger Morphologies and Time-Scales from Simulations of Equal-Mass Gas-Rich Disc Mergers
• NIRCam Performance on JWST In Flight
• Early results from GLASS-JWST. III: Galaxy candidates at z$\sim$9-15
• The GLASS James Webb Space Telescope Early Release Science Program. I. Survey Design and Release Plans
• Discovery and properties of ultra-high redshift galaxies ($9<z<12$) in the JWST ERO SMACS 0723 Field
• CEERS Epoch 1 NIRCam Imaging: Reduction Methods and Simulations Enabling Early JWST Science Results
• Galaxy pairs in the Sloan Digital Sky Survey - IX: Merger-induced AGN activity as traced by the Wide-field Infrared Survey Explorer
• Constraining the properties of AGN host galaxies with Spectral Energy Distribution modeling
• The JWST Early Release Observations
• The Structures of Distant Galaxies I: Galaxy Structures and the Merger Rate to z~3 in the Hubble Ultra-Deep Field
• A massive quiescent galaxy at redshift 4.658
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope II. Multi-object spectroscopy (MOS)
• On the Stellar Populations of Galaxies at z=9-11: The Growth of Metals and Stellar Mass at Early Times
• Confirmation and refutation of very luminous galaxies in the early universe
• Growing supermassive black holes in the late stages of galaxy mergers are heavily obscured
• A JWST/NIRCam Study of Key Contributors to Reionization: The Star-forming and Ionizing Properties of UV-faint $z\sim 7-8$ Galaxies
• Spectroscopic Confirmation of CEERS NIRCam-selected Galaxies at $\mathbf{z}\simeq 8-10$
• Observational constraints on the merger history of galaxies since $z\approx 6$: Probabilistic galaxy pair counts in the CANDELS fields
• JWST's PEARLS: Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results
• JADES Imaging of GN-z11: Revealing the Morphology and Environment of a Luminous Galaxy 430 Myr After the Big Bang
• CEERS Spectroscopic Confirmation of NIRCam-Selected z > 8 Galaxy Candidates with JWST/NIRSpec: Initial Characterization of their Properties
• Mapping galaxy encounters in numerical simulations: The spatial extent of induced star formation
• Evolution of the UV LF from z~15 to z~8 Using New JWST NIRCam Medium-Band Observations over the HUDF/XDF
• Interacting galaxies on FIRE-2: The connection between enhanced star formation and interstellar gas content
• JWST NIRCam+NIRSpec: Interstellar medium and stellar populations of young galaxies with rising star formation and evolving gas reservoirs
• Diagnostics for PopIII galaxies and Direct Collapse Black Holes in the early universe
• A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at $z<3.5$
• The ultraviolet continuum slopes ($\beta$) of galaxies at $\mathbf{z}\simeq 8-16$ from JWST and ground-based near-infrared imaging
• Searching for Extremely Blue UV Continuum Slopes at $z=7-11$ in JWST/NIRCam Imaging: Implications for Stellar Metallicity and Ionizing Photon Escape in Early Galaxies
• The ultra-dense, interacting environment of a dual AGN at z $\sim$ 3.3 revealed by JWST/NIRSpec IFS
• Overview of the JWST Advanced Deep Extragalactic Survey (JADES)
• Galaxy And Mass Assembly (GAMA): the effect of close interactions on star formation in galaxies
• Star formation histories of UV-luminous galaxies at $z\simeq 6.8$: implications for stellar mass assembly at early cosmic times
• Galaxy And Mass Assembly (GAMA): Refining the Local Galaxy Merger Rate using Morphological Information
• Spatially resolved star formation and fuelling in galaxy interactions
• Mergers Do Trigger AGNs out to z $\sim$ 0.6
• EPOCHS VI: The Size and Shape Evolution of Galaxies since z ~ 8 with JWST Observations
• Massive Close Pairs Measure Rapid Galaxy Assembly in Mergers at High Redshift
• Major Merging History in CANDELS. I. Evolution of the Incidence of Massive Galaxy-Galaxy Pairs from z=3 to z~0
• Spectral Templates Optimal for Selecting Galaxies at z > 8 with JWST
• Late-stage galaxy mergers in COSMOS to z~1
• The Star Formation Burstiness and Ionizing Efficiency of Low-mass Galaxies
• The MUSE Hubble Ultra Deep Field Survey. IX. Evolution of galaxy merger fraction since z~6
• The Dependence of Theoretical Synthetic Spectra on $\alpha$-enhancement in Young, Binary Stellar Populations
• Galaxy mergers can rapidly shut down star formation
• New high-precision strong lensing modeling of Abell 2744. Preparing for JWST observations
• A Large Population of Faint 8<z<16 Galaxies Found in the First JWST NIRCam Observations of the NGDEEP Survey
• UV Spectral-Slopes at $z=6-9$ in the Hubble Frontier Fields: Lack of Evidence for Unusual or Pop III Stellar Populations
• Semi-analytic forecasts for JWST -- VI. Simulated lightcones and galaxy clustering predictions
• The discovery of rest-frame UV colour gradients and a diversity of dust morphologies in bright z ~ 7 Lyman-break galaxies
• Quantifying the Effects of Known Unknowns on Inferred High-redshift Galaxy Properties: Burstiness, the IMF, and Nebular Physics
• EPOCHS IV: SED Modelling Assumptions and their impact on the Stellar Mass Function at 6.5 < z < 13.5 using PEARLS and public JWST observations
• JWST's PEARLS: a new lens model for ACT-CL J0102$-$4915, "EL Gordo'', and the first red supergiant star at cosmological distances discovered by JWST
• EPOCHS VII: Discovery of high redshift ($6.5<z<12$) AGN candidates in JWST ERO and PEARLS data
• 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
• Semi-analytic forecasts for JWST -- V. AGN luminosity functions and helium reionization at z = 2-7
• Galaxy Mergers in the Epoch of Reionization I: A JWST Study of Pair Fractions, Merger Rates, and Stellar Mass Accretion Rates at $z=4.5-11.5$
• The ALHAMBRA survey: Accurate merger fractions by PDF analysis of photometric close pairs
• Galaxy interactions are the dominant trigger for local type 2 quasars
• Interacting galaxies in the IllustrisTNG simulations -- IV: Enhanced Supermassive Black Hole Accretion Rates in Post-Merger Galaxies
• How robustly can we constrain the low-mass end of the $z\sim 6-7$ stellar mass function? -- The limits of lensing models and stellar population assumptions in the Hubble Frontier Fields
• Early results from GLASS-JWST XVI: Discovering a bluer z~4-7 Universe through UV slopes
• The role of the cosmic web in the scatter of the galaxy stellar mass - gas metallicity relation
• A 3-Dimensional study of the Local Environment of Bright IRAS Galaxies: The AGN/Starburst connection
• Galaxy interactions in IllustrisTNG-100, I: The power and limitations of visual identification
• Investigating the Effect of Galaxy Interactions on Star Formation at 0.5<z<3.0
• Reconstructing the Assembly of Massive Galaxies. I: The Importance of the Progenitor Effect in the Observed Properties of Quiescent Galaxies at $z\approx 2$
• Changing Ionization Conditions in SDSS Galaxies with AGN as a Function of Environment from Pairs to Clusters
• AGN in post-mergers from the Ultraviolet Near Infrared Optical Northern Survey
• On the dichotomy of Seyfert 2 galaxies: intrinsic differences and evolution
• Paper 1: The JWST PEARLS View of the El Gordo Galaxy Cluster and of the Structure It Magnifies
• Observational Constraints on Correlated Star Formation and Active Galactic Nuclei in Late-Stage Galaxy Mergers
• Galaxy And Mass Assembly (GAMA): the interplay between galaxy mass, SFR and heavy element abundance in paired galaxy sets
• JADES Data Release 3 -- NIRSpec/MSA spectroscopy for 4,000 galaxies in the GOODS fields
• The Cosmos in its Infancy: JADES Galaxy Candidates at z > 8 in GOODS-S and GOODS-N
• Nuclear activity in $z<0.3$ QSO 2's mainly triggered by galaxy mergers
• Does AGN Fraction Depend on Redshift or Luminosity? An Extinction-Free Test by 18-band Mid-infrared SED Fitting in the AKARI NEP Wide Field
• The Subtle Effects of Mergers on Star Formation in Nearby Galaxies
• COSMOS-Web: Intrinsically Luminous z$\gtrsim$10 Galaxy Candidates Test Early Stellar Mass Assembly
• The galaxy UV luminosity function at $\mathbf{z}\simeq 11$ from a suite of public JWST ERS, ERO and Cycle-1 programs
• Unveiling the distant Universe: Characterizing $z\ge 9$ Galaxies in the first epoch of COSMOS-Web
• When relics were made: vigorous stellar rotation and low dark matter content in the massive ultra-compact galaxy GS-9209 at z=4.66
• EPOCHS I. The Discovery and Star Forming Properties of Galaxies in the Epoch of Reionization at $6.5<z<18$ with PEARLS and Public JWST data
• Bursting at the seams: the star-forming main sequence and its scatter at z=3-9 using NIRCam photometry from JADES
• Detection of new galaxy candidates at z > 11 in the JADES field using JWST NIRCam
• Constraining the major merger history of $z\sim 3-9$ galaxies using JADES: dominant in-situ star formation

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• Galaxy Mergers in the Epoch of Reionization I: A JWST Study of Pair Fractions, Merger Rates, and Stellar Mass Accretion Rates at $z=4.5-11.5$
• The dawn of disks: unveiling the turbulent ionised gas kinematics of the galaxy population at $z\sim 4-6$ with JWST/NIRCam grism spectroscopy
• When relics were made: vigorous stellar rotation and low dark matter content in the massive ultra-compact galaxy GS-9209 at z=4.66
• Nearby dwarf galaxies with extreme star formation rates: a window into dwarf-galaxy evolution in the early Universe
• Angular correlation functions of bright Lyman-break galaxies at $3\lesssim \mathbf{z}\lesssim 5$