Letter to the Editor

Galactic warps: From cosmic noon to the current epoch

¹ Pulkovo Astronomical Observatory, Russian Academy of Sciences, St.Petersburg 196140, Russia
² Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia
³ Department of Physics and Astronomy, N283 ESC, Brigham Young University, Provo UT 84602, USA
⁴ Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz 369167, Russia

^⋆ Corresponding author.

Received: 1 April 2025
Accepted: 16 April 2025

Abstract

Context. Approximately half of all disk galaxies exhibit appreciable warps in both their stellar and H I disks. The typical warp amplitude is small (a few degrees) and only becomes noticeable at the periphery of the galaxy disk. As a result, warps remain a relatively poorly studied phenomenon.

Aims. In this study, we investigate a large sample of distant edge-on galaxies (approximately 1000 objects) in order to examine the frequency and characteristics of stellar disk warps up to a redshift of z ∼ 2.

Methods. For the selected galaxies, we used Hubble Space Telescope data from the Cosmic Evolution Survey field and JWST observations from the Cosmic Dawn Center Archive. We measured the properties of disk warps and investigated their evolution as a function of redshift.

Results. Our results indicate a potential evolution in the observed frequency of strong S-shaped warps (with an amplitude greater than 4°) in stellar disks as a function of redshift. At z ≈ 2, the frequency of strong warps reaches approximately 50%, while at z ≈ 0, this fraction decreases to around 10–15%. We attribute the observed evolution in the occurrence of strong warps to the changing frequency of galaxy interactions and mergers. If galaxy interactions represent one of the primary mechanisms responsible for the formation of warps, then the prevalence of vertical disk deformations should increase in tandem with the rising interaction and merger rate.