Letter to the Editor

JWST reveals a high fraction of disk breaks at 1 ≤ z ≤ 3

¹ Department of Astronomy, Peking University, 5 Yiheyuan Road, Haidian District, Beijing 100871, PR China
² The Kavli Institute for Astronomy and Astrophysics, Peking University, 5 Yiheyuan Road, Haidian District, Beijing 100871, PR China
³ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
e-mail: phyyueyu@gmail.com; syu@mpifr-bonn.mpg.de

Received: 17 January 2024
Accepted: 6 February 2024

Abstract

We analyzed the deconvolved surface brightness profiles of 247 massive and angularly large disk galaxies at 1 ≤ z ≤ 3 to study high-redshift disk breaks, using F356W-band images from the Cosmic Evolution Early Release Science survey (CEERS). We found that 12.6% of these galaxies exhibit type I (exponential) profiles, 56.7% exhibit type II (down-bending) profiles, and 34.8% exhibit type III (up-bending) profiles. Moreover, we showed that galaxies that are more massive, centrally concentrated, or redder, tend to show fewer type II and more type III breaks. These fractions and the detected dependencies on galaxy properties are in good agreement with those observed in the Local Universe. In particular, the ratio of the type II disk break radius to the bar radius in barred galaxies typically peaks at a value of 2.25, perhaps due to bar-induced radial migration. However, the timescale for secular evolution may be too lengthy to explain the observed breaks at such high redshifts. Instead, violent disk instabilities may be responsible, where spiral arms and clumps torque fling out the material, leading to the formation of outer exponential disks. Our results provide further evidence for the assertion that the Hubble Sequence was already in place during these early periods.