Paper

Galaxy Zoo JWST: Up to 75% of discs are featureless at \\(3

Jewell, S M, Garland, I L, Simmons, B D, tson, L, Makechemu, J S, Géron, T, Dickinson, H, Thorne, M R, O'Ryan, D, Walmsley, M, Smethurst, R J, Pacucci, F, Mantha, K B, Holwerda, B, Lyu, Y, Tarrasse, M, Lintott, C J, Kartaltepe, J S, Calabrò, M, Roberts, H, Lucas, R, Masters, K L, Kruk, S, Koekemoer, A M

2025

Overview

We have not yet observed the epoch at which disc galaxies emerge in the Universe. While high-\\(z\\) measurements of large-scale features such as bars and spiral arms trace the evolution of disc galaxies, such methods cannot directly quantify featureless discs in the early Universe. Here we identify a substantial population of apparently featureless disc galaxies in the Cosmic Evolution Early Release Science (CEERS) survey by combining quantitative visual morphologies of \\( 7,000\\) galaxies from the Galaxy Zoo JWST CEERS project with a public catalogue of expert visual and parametric morphologies. While the highest-redshift featured disc we identify is at \\(z_phot=5.5\\), the highest-redshift featureless disc we identify is at \\(z_phot=7.4\\). The distribution of Sérsic indices for these featureless systems suggests that they truly are dynamically cold: disc-dominated systems have existed since at least \\(z 7.4\\). We place upper limits on the featureless disc fraction as a function of redshift, and show that up to \\(75\\%\\) of discs are featureless at \\(3.0

• Publisher: Cornell University Library, arXiv.org
• Subject: Disk galaxies / Galactic structure / Morphology / Red shift / Stars & galaxies / Universe