Influence of mergers on LyC escape of high redshift galaxies

Abstract

Aims: We investigate the impact of galaxy mergers on the Lyman Continuum (LyC) radiation escape, fesc, from high-redshift galaxies. Methods: We post-process ~ 6e5 galaxies (redshift 5.2 < z < 10) extracted from the TNG50 cosmological simulation using a physically motivated analytic model for LyC escape. Results: Galaxies that have not experienced a merger for the last ~ 700 Myr have an average fesc ~ 3%, which increases to up to 14% immediately following a merger. The strongest effect can be observed in galaxies with stellar masses of ~ 1e7 Msun. We attribute the increase in the escape fraction to two main factors: (i) accretion of metal-poor gas onto the central region of a galaxy, which feeds star formation and LyC emission; and (ii) displacement of neutral gas relative to star-forming regions, which reduces the optical depth to LyC photons. We additionally examine how proximity to other galaxies influences LyC escape, finding that galaxies with more neighbors tend to have more frequent mergers, and thus a higher LyC leakage. However, galaxies in overdense regions tend to have a larger LyC escape fraction independently from mergers, because of their higher gas inflow, and consequent increase in the star formation rate. The increase in both mergers and gas inflow could contribute to low-mass galaxies ionizing proximity zones of high-z Ly-alpha leakers recently observed with JWST.

arXiv comment8 pages, 6 figures, Submitted to Astronomy & Astrophysics

References in corpus (40)

• Galactic Stellar and Substellar Initial Mass Function
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• Populating a cluster of galaxies - I. Results at z=0
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Cosmological SPH simulations: A hybrid multi-phase model for star formation
• Simulating Galaxy Formation with the IllustrisTNG Model
• Simulating galaxy formation with black hole driven thermal and kinetic feedback
• An 800-million-solar-mass black hole in a significantly neutral Universe at redshift 7.5
• First Results from the TNG50 Simulation: The evolution of stellar and gaseous disks across cosmic time
• A New Calculation of the Ionizing Background Spectrum and the Effects of HeII Reionization
• The evolution of the galaxy UV luminosity function at redshifts z ~ 8-15 from deep JWST and ground-based near-infrared imaging
• The size - virial radius relation of galaxies
• Hydrogen reionisation ends by $z=5.3$: Lyman-$\alpha$ optical depth measured by the XQR-30 sample
• The First Billion Years Project: The escape fraction of ionizing photons in the epoch of reionization
• Observations of the Lyman-$\alpha$ Universe
• The role of mergers and halo spin in shaping galaxy morphology
• Spectroscopic Confirmation of CEERS NIRCam-selected Galaxies at $\mathbf{z}\simeq 8-10$
• Direct Lyman continuum and Lyman-alpha escape observed at redshift 4
• The Low-Redshift Lyman Continuum Survey I: New, Diverse Local Lyman-Continuum Emitters
• A parsec-resolution simulation of the Antennae galaxies: Formation of star clusters during the merger
• Evolution of the UV LF from z~15 to z~8 Using New JWST NIRCam Medium-Band Observations over the HUDF/XDF
• The Far-Ultraviolet Continuum Slope as a Lyman Continuum Escape Estimator at High-redshift
• No missing photons for reionization: moderate ionizing photon escape fractions from the FIRE-2 simulations
• Accurately predicting the escape fraction of ionizing photons using restframe ultraviolet absorption lines
• Reionization with galaxies and active galactic nuclei
• The THESAN project: Lyman-alpha emission and transmission during the Epoch of Reionization
• The Lyman Continuum Escape Survey -- II: Ionizing Radiation as a Function of the [OIII]/[OII] Line Ratio
• Evolution in the Escape Fraction of Ionizing Photons and the Decline in Strong Lya Emission from z>6 Galaxies
• The formation of low metallicity globular clusters in dwarf galaxy mergers
• Dark-ages Reionization and Galaxy Formation Simulation - X. The small contribution of quasars to reionization
• Probing Intergalactic Neutral Hydrogen by the Lyman Alpha Red Damping Wing of Gamma-Ray Burst 130606A Afterglow Spectrum at z = 5.913
• Three Lyman-alpha emitting galaxies within a quasar proximity zone at z=5.8
• The Lyman Continuum Escape Survey: Connecting Time-Dependent [OIII] and [OII] Line Emission with Lyman Continuum Escape Fraction in Simulations of Galaxy Formation
• Deciphering Lyman-$\alpha$ Emission Deep into the Epoch of Reionisation
• New Methods for Identifying Lyman Continuum Leakers and Reionization-Epoch Analogues
• Large scale simulations of H and He reionization and heating driven by stars and more energetic sources
• ERGO-ML I: Inferring the assembly histories of IllustrisTNG galaxies from integral observable properties via invertible neural networks
• Lyman Continuum Escape Fraction in Ly$\alpha$ Emitters at $z\simeq 3.1$
• Ionizing photon production and escape fractions during cosmic reionization in the TNG50 simulation
• Physically motivated modeling of LyC escape fraction during reionization

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