Galaxy morphology from z ∼ 6 through the lens of JWST

Abstract

The James Webb Space Telescope's (JWST's) unprecedented combination of sensitivity, spatial resolution, and infrared coverage has enabled a new era of galaxy morphology exploration across most of cosmic history. We analyze the near-infrared (NIR $ rest-frame morphologies of galaxies with $ M_*/M_ in the redshift range of $0<z<6$, compare with previous HST-based results and release the first JWST-based morphological catalog of $ galaxies in the CEERS survey. We classified the galaxies in our sample into four main broad classes: spheroid, disk+spheroid, disk, and disturbed, based on imaging with four filters: $F150W$, $F200W$, $F356W$, and $F444W.$ We used convolutional neural networks (CNNs) trained on HST/WFC3 labeled images and domain-adapted to JWST/NIRCam. We find that $ and $ of galaxies at $z<3$ have the same early and late and regular and irregular classification, respectively, in JWST and HST imaging when considering similar wavelengths. For small (large) and faint objects, JWST-based classifications tend to systematically present less bulge-dominated systems (peculiar galaxies) than HST-based ones, but the impact on the reported evolution of morphological fractions is less than $ Using JWST-based morphologies at the same rest-frame wavelength ($ we confirm an increase in peculiar galaxies and a decrease in bulge-dominated galaxies with redshift, as reported in previous HST-based works, suggesting that the stellar mass distribution, in addition to light distribution, is more disturbed in the early universe. However, we find that undisturbed disk-like systems already dominate the high-mass end of the late-type galaxy population ($ M_*/M_ at $z and bulge-dominated galaxies also exist at these early epochs, confirming a rich and evolved morphological diversity of galaxies $ Gyr after the Big Bang. Finally, we find that the morphology-quenching relation is already in place for massive galaxies at $z>3$, with massive quiescent galaxies ($ M_*/M_ being predominantly bulge-dominated.

Turbulent Gas-rich Disks at High Redshift: Bars and Bulges in a Radial Shear Flow

“…In light of recent developments, our view of disk formation in the early Universe is undergoing a radical overhaul. With the launch of the James Webb Space Telescope (JWST), a new window into the distant Universe has revealed that (mostly thin) disk galaxies 5 dominate the population out to at least z ≈ 6 (Ferreira et al 2023;Kartaltepe et al 2023;Robertson et al 2023), although further analysis is needed (Huertas-Company et al 2024). We can use bars (and bulges) to learn about the early history of galaxies, particularly when the phenomenon can be traced to the highest redshifts.…”

Calibrating Nonparametric Morphological Indicators from JWST Images for Galaxies over 0.5 < z < 3

“…However, the recent multiband images from the JWST/NIRCam have dramatically altered our understanding of the galaxy morphology of distant galaxies. An increasing body of evidence now suggests that these galaxies are predominantly disk dominated (Ferreira et al 2022(Ferreira et al , 2023Kartaltepe et al 2023), and remarkably, the Hubble sequence is observable even at z = 6 (Huertas- Company et al 2024). These most recent findings underscore the necessity to reassess the evolutionary trend in morphological structures of galaxies across different rest-frame wavelengths and redshifts.…”